Bump version to 3.8.0

This shouldn't affect the behaviour of existing tests, other than an NPE being replaced with an assertNotNull().

TestNets.md

@@ -52,14 +52,13 @@
 
 ## Single-node testnet
 
-A single-node testnet is possible with code modifications, for basic testing, or to more easily start a new testnet.
-To do so, follow these steps:
-- Comment out the `if (mintedLastBlock) { }` conditional in BlockMinter.java
-- Comment out the `minBlockchainPeers` validation in Settings.validate()
-- Set `minBlockchainPeers` to 0 in settings.json
-- Set `Synchronizer.RECOVERY_MODE_TIMEOUT` to `0`
-- All other steps should remain the same. Only a single reward share key is needed.
-- Remember to put these values back after introducing other nodes
+A single-node testnet is possible with an additional settings, or to more easily start a new testnet.
+Just add this setting:
+```
+"singleNodeTestnet": true
+```
+This will automatically allow multiple consecutive blocks to be minted, as well as setting minBlockchainPeers to 0.
+Remember to put these values back after introducing other nodes
 
 ## Fixed network
 
@@ -93,3 +92,32 @@ Your options are:
 - `qort` tool, but prepend with one-time shell variable: `BASE_URL=some-node-hostname-or-ip:port qort ......`
 - `peer-heights`, but use `-t` option, or `BASE_URL` shell variable as above
 
+## Example settings-test.json
+```
+{
+  "isTestNet": true,
+  "bitcoinNet": "TEST3",
+  "repositoryPath": "db-testnet",
+  "blockchainConfig": "testchain.json",
+  "minBlockchainPeers": 1,
+  "apiDocumentationEnabled": true,
+  "apiRestricted": false,
+  "bootstrap": false,
+  "maxPeerConnectionTime": 999999999,
+  "localAuthBypassEnabled": true,
+  "singleNodeTestnet": true,
+  "recoveryModeTimeout": 0
+}
+```
+
+## Quick start
+Here are some steps to quickly get a single node testnet up and running with a generic minting account:
+1. Start with template `settings-test.json`, and create a `testchain.json` based on mainnet's blockchain.json (or obtain one from Qortal developers). These should be in the same directory as the jar.
+2. Make sure feature triggers and other timestamp/height activations are correctly set. Generally these would be `0` so that they are enabled from the start.
+3. Set a recent genesis `timestamp` in testchain.json, and add this reward share entry:
+`{ "type": "REWARD_SHARE", "minterPublicKey": "DwcUnhxjamqppgfXCLgbYRx8H9XFPUc2qYRy3CEvQWEw", "recipient": "QbTDMss7NtRxxQaSqBZtSLSNdSYgvGaqFf", "rewardSharePublicKey": "CRvQXxFfUMfr4q3o1PcUZPA4aPCiubBsXkk47GzRo754", "sharePercent": 0 },`
+4. Start the node, passing in settings-test.json, e.g: `java -jar qortal.jar settings-test.json`
+5. Once started, add the corresponding minting key to the node:
+`curl -X POST "http://localhost:62391/admin/mintingaccounts" -d "F48mYJycFgRdqtc58kiovwbcJgVukjzRE4qRRtRsK9ix"`
+6. Alternatively you can use your own minting account instead of the generic one above.
+7. After a short while, blocks should be minted from the genesis timestamp until the current time.

WindowsInstaller/Qortal.aip

@@ -17,10 +17,10 @@
     <ROW Property="Manufacturer" Value="Qortal"/>
     <ROW Property="MsiLogging" MultiBuildValue="DefaultBuild:vp"/>
     <ROW Property="NTP_GOOD" Value="false"/>
-    <ROW Property="ProductCode" Value="1033:{E5597539-098E-4BA6-99DF-4D22018BC0D3} 1049:{2B5E55A2-142A-4BED-B3B9-5657162282B7} 2052:{6F19171F-4743-4127-B191-AAFA3FA885D2} 2057:{A1B3108D-EC5D-47A1-AEE4-DBD956E682FB} " Type="16"/>
+    <ROW Property="ProductCode" Value="1033:{ADE0C9E9-F7D9-4829-8626-8571C735C4D7} 1049:{F5230C0A-9D8C-4C70-AC72-17CECC8273B8} 2052:{D5A0760C-E5B3-4C4C-97B0-81CC445F07B9} 2057:{EF5EF0BE-0B00-4F5C-A2A0-DF2CB82FF20D} " Type="16"/>
     <ROW Property="ProductLanguage" Value="2057"/>
     <ROW Property="ProductName" Value="Qortal"/>
-    <ROW Property="ProductVersion" Value="3.4.3" Type="32"/>
+    <ROW Property="ProductVersion" Value="3.6.3" Type="32"/>
     <ROW Property="RECONFIG_NTP" Value="true"/>
     <ROW Property="REMOVE_BLOCKCHAIN" Value="YES" Type="4"/>
     <ROW Property="REPAIR_BLOCKCHAIN" Value="YES" Type="4"/>
@@ -212,7 +212,7 @@
     <ROW Component="ADDITIONAL_LICENSE_INFO_71" ComponentId="{12A3ADBE-BB7A-496C-8869-410681E6232F}" Directory_="jdk.zipfs_Dir" Attributes="0" KeyPath="ADDITIONAL_LICENSE_INFO_71" Type="0"/>
     <ROW Component="ADDITIONAL_LICENSE_INFO_8" ComponentId="{D53AD95E-CF96-4999-80FC-5812277A7456}" Directory_="java.naming_Dir" Attributes="0" KeyPath="ADDITIONAL_LICENSE_INFO_8" Type="0"/>
     <ROW Component="ADDITIONAL_LICENSE_INFO_9" ComponentId="{6B7EA9B0-5D17-47A8-B78C-FACE86D15E01}" Directory_="java.net.http_Dir" Attributes="0" KeyPath="ADDITIONAL_LICENSE_INFO_9" Type="0"/>
-    <ROW Component="AI_CustomARPName" ComponentId="{F17029E8-CCC4-456D-B4AC-1854C81C46B6}" Directory_="APPDIR" Attributes="260" KeyPath="DisplayName" Options="1"/>
+    <ROW Component="AI_CustomARPName" ComponentId="{F4F774B9-18DC-4740-9552-EA16B98801C9}" Directory_="APPDIR" Attributes="260" KeyPath="DisplayName" Options="1"/>
     <ROW Component="AI_ExePath" ComponentId="{3644948D-AE0B-41BB-9FAF-A79E70490A08}" Directory_="APPDIR" Attributes="260" KeyPath="AI_ExePath"/>
     <ROW Component="APPDIR" ComponentId="{680DFDDE-3FB4-47A5-8FF5-934F576C6F91}" Directory_="APPDIR" Attributes="0"/>
     <ROW Component="AccessBridgeCallbacks.h" ComponentId="{288055D1-1062-47A3-AA44-5601B4E38AED}" Directory_="bridge_Dir" Attributes="0" KeyPath="AccessBridgeCallbacks.h" Type="0"/>
@@ -1173,7 +1173,7 @@
     <ROW Action="AI_STORE_LOCATION" Type="51" Source="ARPINSTALLLOCATION" Target="[APPDIR]"/>
     <ROW Action="AI_SetPermissions" Type="11265" Source="userAccounts.dll" Target="OnSetPermissions" WithoutSeq="true"/>
     <ROW Action="CustomizeLog4j2PropertiesScript" Type="3109" Target="Script Text" TargetUnformatted="var actionData = Session.Property(&quot;CustomActionData&quot;);&#13;&#10;var actionDataArray = actionData.split(&quot;|&quot;);&#13;&#10;var appDir = actionDataArray[0];&#13;&#10;var dataFolder = actionDataArray[1] + actionDataArray[2] + &quot;\\&quot;;&#13;&#10;&#13;&#10;var ForReading = 1, ForWriting = 2, ForAppending = 8;&#13;&#10;var fso = new ActiveXObject(&quot;Scripting.FileSystemObject&quot;);&#13;&#10;&#13;&#10;// Make copy&#13;&#10;fso.CopyFile(appDir + &quot;log4j2.properties&quot;, appDir + &quot;log4j2-orig.properties&quot;, true); // overwrite&#13;&#10;&#13;&#10;// Rewrite %AppDir%\log4j2.properties to update logfile storage path&#13;&#10;var fin = fso.OpenTextFile(appDir + &quot;log4j2-orig.properties&quot;, ForReading, false); // no create&#13;&#10;var fout = fso.OpenTextFile(appDir + &quot;log4j2.properties&quot;, ForWriting, true); // can create&#13;&#10;&#13;&#10;// Copy lines with rewriting where necessary&#13;&#10;while( !fin.AtEndOfStream ) {&#13;&#10;&#9;var line = fin.ReadLine();&#13;&#10;&#13;&#10;&#9;var start = line.indexOf(&quot;property.dirname&quot;);&#13;&#10;&#9;if (start &gt; 0) {&#13;&#10;&#9;&#9;// line: # property.dirname = ...appdata...&#13;&#10;&#9;&#9;// uncomment/replace this line for Windows&#13;&#10;&#9;&#9;fout.WriteLine( &quot;property.dirname = &quot; + dataFolder.split(&apos;\\&apos;).join(&apos;\\\\&apos;) );&#13;&#10;&#9;} else {&#13;&#10;&#9;&#9;// not found - output verbatim&#13;&#10;&#9;&#9;fout.WriteLine( line );&#13;&#10;&#9;}&#13;&#10;}&#13;&#10;&#13;&#10;fin.Close();&#13;&#10;fout.Close();&#13;&#10;" AdditionalSeq="AI_DATA_SETTER_4"/>
-    <ROW Action="CustomizeSettingsJsonScript" Type="3109" Target="Script Text" TargetUnformatted="var actionData = Session.Property(&quot;CustomActionData&quot;);&#13;&#10;var actionDataArray = actionData.split(&quot;|&quot;);&#13;&#10;var appDir = actionDataArray[0];&#13;&#10;var dataFolder = actionDataArray[1] + actionDataArray[2] + &quot;\\&quot;;&#13;&#10;&#13;&#10;var ForReading = 1, ForWriting = 2, ForAppending = 8;&#13;&#10;var fso = new ActiveXObject(&quot;Scripting.FileSystemObject&quot;);&#13;&#10;&#13;&#10;// Create basic %APPDIR%\settings.json with path to real settings.json in dataFolder&#13;&#10;var fts = fso.OpenTextFile(appDir + &quot;settings.json&quot;, ForWriting, true);&#13;&#10;&#13;&#10;fts.WriteLine( &quot;{&quot; );&#13;&#10;// We need to escape Windows path backslashes to keep JSON valid&#13;&#10;fts.WriteLine( &quot;  \&quot;userPath\&quot;: \&quot;&quot; + dataFolder.split(&apos;\\&apos;).join(&apos;\\\\&apos;) + &quot;\&quot;&quot; );&#13;&#10;fts.WriteLine( &quot;}&quot; );&#13;&#10;&#13;&#10;fts.Close();&#13;&#10;&#13;&#10;// Make copy&#13;&#10;fso.CopyFile(dataFolder + &quot;settings.json&quot;, dataFolder + &quot;settings-orig.json&quot;, true); // overwrite&#13;&#10;&#13;&#10;// Rewrite settings.json to update repository path&#13;&#10;var fin = fso.OpenTextFile(dataFolder + &quot;settings-orig.json&quot;, ForReading, false);&#13;&#10;var fout = fso.OpenTextFile(dataFolder + &quot;settings.json&quot;, ForWriting, true);&#13;&#10;&#13;&#10;// First line should contain opening brace&#13;&#10;fout.WriteLine( fin.ReadLine() );&#13;&#10;&#13;&#10;// Append our entries&#13;&#10;fout.WriteLine( &quot;  \&quot;repositoryPath\&quot;: \&quot;&quot; + dataFolder.split(&apos;\\&apos;).join(&apos;\\\\&apos;) + &quot;db\&quot;,&quot; );&#13;&#10;fout.WriteLine( &quot;  \&quot;dataPath\&quot;: \&quot;&quot; + dataFolder.split(&apos;\\&apos;).join(&apos;\\\\&apos;) + &quot;data\&quot;,&quot; );&#13;&#10;&#13;&#10;// copy rest of settings&#13;&#10;while( !fin.AtEndOfStream ) {&#13;&#10;&#9;fout.WriteLine( fin.ReadLine() );&#13;&#10;}&#13;&#10;&#13;&#10;fin.Close();&#13;&#10;fout.Close();&#13;&#10;" AdditionalSeq="AI_DATA_SETTER_3"/>
+    <ROW Action="CustomizeSettingsJsonScript" Type="3109" Target="Script Text" TargetUnformatted="var actionData = Session.Property(&quot;CustomActionData&quot;);&#13;&#10;var actionDataArray = actionData.split(&quot;|&quot;);&#13;&#10;var appDir = actionDataArray[0];&#13;&#10;var dataFolder = actionDataArray[1] + actionDataArray[2] + &quot;\\&quot;;&#13;&#10;&#13;&#10;var ForReading = 1, ForWriting = 2, ForAppending = 8;&#13;&#10;var fso = new ActiveXObject(&quot;Scripting.FileSystemObject&quot;);&#13;&#10;&#13;&#10;// Create basic %APPDIR%\settings.json with path to real settings.json in dataFolder&#13;&#10;var fts = fso.OpenTextFile(appDir + &quot;settings.json&quot;, ForWriting, true);&#13;&#10;&#13;&#10;fts.WriteLine( &quot;{&quot; );&#13;&#10;// We need to escape Windows path backslashes to keep JSON valid&#13;&#10;fts.WriteLine( &quot;  \&quot;userPath\&quot;: \&quot;&quot; + dataFolder.split(&apos;\\&apos;).join(&apos;\\\\&apos;) + &quot;\&quot;&quot; );&#13;&#10;fts.WriteLine( &quot;}&quot; );&#13;&#10;&#13;&#10;fts.Close();&#13;&#10;&#13;&#10;// Make copy&#13;&#10;fso.CopyFile(dataFolder + &quot;settings.json&quot;, dataFolder + &quot;settings-orig.json&quot;, true); // overwrite&#13;&#10;&#13;&#10;// Rewrite settings.json to update repository path&#13;&#10;var fin = fso.OpenTextFile(dataFolder + &quot;settings-orig.json&quot;, ForReading, false);&#13;&#10;var fout = fso.OpenTextFile(dataFolder + &quot;settings.json&quot;, ForWriting, true);&#13;&#10;&#13;&#10;// First line should contain opening brace&#13;&#10;fout.WriteLine( fin.ReadLine() );&#13;&#10;&#13;&#10;// Append our entries&#13;&#10;fout.WriteLine( &quot;  \&quot;repositoryPath\&quot;: \&quot;&quot; + dataFolder.split(&apos;\\&apos;).join(&apos;\\\\&apos;) + &quot;db\&quot;,&quot; );&#13;&#10;fout.WriteLine( &quot;  \&quot;dataPath\&quot;: \&quot;&quot; + dataFolder.split(&apos;\\&apos;).join(&apos;\\\\&apos;) + &quot;data\&quot;,&quot; );&#13;&#10;fout.WriteLine( &quot;  \&quot;walletsPath\&quot;: \&quot;&quot; + dataFolder.split(&apos;\\&apos;).join(&apos;\\\\&apos;) + &quot;wallets\&quot;,&quot; );&#13;&#10;fout.WriteLine( &quot;  \&quot;listsPath\&quot;: \&quot;&quot; + dataFolder.split(&apos;\\&apos;).join(&apos;\\\\&apos;) + &quot;lists\&quot;,&quot; );&#13;&#10;&#13;&#10;// copy rest of settings&#13;&#10;while( !fin.AtEndOfStream ) {&#13;&#10;&#9;fout.WriteLine( fin.ReadLine() );&#13;&#10;}&#13;&#10;&#13;&#10;fin.Close();&#13;&#10;fout.Close();&#13;&#10;" AdditionalSeq="AI_DATA_SETTER_3"/>
     <ROW Action="DetectRunningProcess" Type="1" Source="aicustact.dll" Target="DetectProcess" Options="3" AdditionalSeq="AI_DATA_SETTER_8"/>
     <ROW Action="DetectW32Time" Type="1" Source="aicustact.dll" Target="DetectService" Options="3" AdditionalSeq="AI_DATA_SETTER_11"/>
     <ROW Action="NTP_config" Type="3090" Source="ntpcfg.bat"/>

lib/org/ciyam/AT/1.4.0/AT-1.4.0.pom

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>org.ciyam</groupId>
+  <artifactId>AT</artifactId>
+  <version>1.4.0</version>
+  <description>POM was created from install:install-file</description>
+</project>

lib/org/ciyam/AT/maven-metadata-local.xml

@@ -3,14 +3,15 @@
   <groupId>org.ciyam</groupId>
   <artifactId>AT</artifactId>
   <versioning>
-    <release>1.3.8</release>
+    <release>1.4.0</release>
     <versions>
       <version>1.3.4</version>
       <version>1.3.5</version>
       <version>1.3.6</version>
       <version>1.3.7</version>
       <version>1.3.8</version>
+      <version>1.4.0</version>
     </versions>
-    <lastUpdated>20200925114415</lastUpdated>
+    <lastUpdated>20221105114346</lastUpdated>
   </versioning>
 </metadata>

pom.xml

@@ -3,7 +3,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>org.qortal</groupId>
 	<artifactId>qortal</artifactId>
-	<version>3.6.3</version>
+	<version>3.8.0</version>
 	<packaging>jar</packaging>
 	<properties>
 		<skipTests>true</skipTests>
@@ -11,7 +11,7 @@
 		<bitcoinj.version>0.15.10</bitcoinj.version>
 		<bouncycastle.version>1.69</bouncycastle.version>
 		<build.timestamp>${maven.build.timestamp}</build.timestamp>
-		<ciyam-at.version>1.3.8</ciyam-at.version>
+		<ciyam-at.version>1.4.0</ciyam-at.version>
 		<commons-net.version>3.6</commons-net.version>
 		<commons-text.version>1.8</commons-text.version>
 		<commons-io.version>2.6</commons-io.version>

src/main/java/org/qortal/account/Account.java

@@ -211,7 +211,8 @@ public class Account {
 		if (level != null && level >= BlockChain.getInstance().getMinAccountLevelToMint())
 			return true;
 
-		if (Account.isFounder(accountData.getFlags()))
+		// Founders can always mint, unless they have a penalty
+		if (Account.isFounder(accountData.getFlags()) && accountData.getBlocksMintedPenalty() == 0)
 			return true;
 
 		return false;
@@ -222,6 +223,11 @@ public class Account {
 		return this.repository.getAccountRepository().getMintedBlockCount(this.address);
 	}
 
+	/** Returns account's blockMintedPenalty or null if account not found in repository. */
+	public Integer getBlocksMintedPenalty() throws DataException {
+		return this.repository.getAccountRepository().getBlocksMintedPenaltyCount(this.address);
+	}
+
 
 	/** Returns whether account can build reward-shares.
 	 * <p>
@@ -243,7 +249,7 @@ public class Account {
 		if (level != null && level >= BlockChain.getInstance().getMinAccountLevelToRewardShare())
 			return true;
 
-		if (Account.isFounder(accountData.getFlags()))
+		if (Account.isFounder(accountData.getFlags()) && accountData.getBlocksMintedPenalty() == 0)
 			return true;
 
 		return false;
@@ -271,7 +277,7 @@ public class Account {
 	/**
 	 * Returns 'effective' minting level, or zero if account does not exist/cannot mint.
 	 * <p>
-	 * For founder accounts, this returns "founderEffectiveMintingLevel" from blockchain config.
+	 * For founder accounts with no penalty, this returns "founderEffectiveMintingLevel" from blockchain config.
 	 * 
 	 * @return 0+
 	 * @throws DataException
@@ -281,7 +287,8 @@ public class Account {
 		if (accountData == null)
 			return 0;
 
-		if (Account.isFounder(accountData.getFlags()))
+		// Founders are assigned a different effective minting level, as long as they have no penalty
+		if (Account.isFounder(accountData.getFlags()) && accountData.getBlocksMintedPenalty() == 0)
 			return BlockChain.getInstance().getFounderEffectiveMintingLevel();
 
 		return accountData.getLevel();
@@ -289,8 +296,6 @@ public class Account {
 
 	/**
 	 * Returns 'effective' minting level, or zero if reward-share does not exist.
-	 * <p>
-	 * this is being used on src/main/java/org/qortal/api/resource/AddressesResource.java to fulfil the online accounts api call
 	 * 
 	 * @param repository
 	 * @param rewardSharePublicKey
@@ -309,7 +314,7 @@ public class Account {
 	/**
 	 * Returns 'effective' minting level, with a fix for the zero level.
 	 * <p>
-	 * For founder accounts, this returns "founderEffectiveMintingLevel" from blockchain config.
+	 * For founder accounts with no penalty, this returns "founderEffectiveMintingLevel" from blockchain config.
 	 *
 	 * @param repository
 	 * @param rewardSharePublicKey
@@ -322,7 +327,7 @@ public class Account {
 		if (rewardShareData == null)
 			return 0;
 
-		else if(!rewardShareData.getMinter().equals(rewardShareData.getRecipient()))//the minter is different than the recipient this means sponsorship
+		else if (!rewardShareData.getMinter().equals(rewardShareData.getRecipient())) // Sponsorship reward share
 			return 0;
 
 		Account rewardShareMinter = new Account(repository, rewardShareData.getMinter());

src/main/java/org/qortal/account/SelfSponsorshipAlgoV1.java

@@ -0,0 +1,362 @@
+package org.qortal.account;
+
+import org.qortal.api.resource.TransactionsResource;
+import org.qortal.asset.Asset;
+import org.qortal.data.account.AccountData;
+import org.qortal.data.naming.NameData;
+import org.qortal.data.transaction.*;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.transaction.Transaction.TransactionType;
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class SelfSponsorshipAlgoV1 {
+
+    private final Repository repository;
+    private final String address;
+    private final AccountData accountData;
+    private final long snapshotTimestamp;
+    private final boolean override;
+
+    private int registeredNameCount = 0;
+    private int suspiciousCount = 0;
+    private int suspiciousPercent = 0;
+    private int consolidationCount = 0;
+    private int bulkIssuanceCount = 0;
+    private int recentSponsorshipCount = 0;
+
+    private List<RewardShareTransactionData> sponsorshipRewardShares = new ArrayList<>();
+    private final Map<String, List<TransactionData>> paymentsByAddress = new HashMap<>();
+    private final Set<String> sponsees = new LinkedHashSet<>();
+    private Set<String> consolidatedAddresses = new LinkedHashSet<>();
+    private final Set<String> zeroTransactionAddreses = new LinkedHashSet<>();
+    private final Set<String> penaltyAddresses = new LinkedHashSet<>();
+
+    public SelfSponsorshipAlgoV1(Repository repository, String address, long snapshotTimestamp, boolean override) throws DataException {
+        this.repository = repository;
+        this.address = address;
+        this.accountData = this.repository.getAccountRepository().getAccount(this.address);
+        this.snapshotTimestamp = snapshotTimestamp;
+        this.override = override;
+    }
+
+    public String getAddress() {
+        return this.address;
+    }
+
+    public Set<String> getPenaltyAddresses() {
+        return this.penaltyAddresses;
+    }
+
+
+    public void run() throws DataException {
+        this.fetchSponsorshipRewardShares();
+        if (this.sponsorshipRewardShares.isEmpty()) {
+            // Nothing to do
+            return;
+        }
+
+        this.findConsolidatedRewards();
+        this.findBulkIssuance();
+        this.findRegisteredNameCount();
+        this.findRecentSponsorshipCount();
+
+        int score = this.calculateScore();
+        if (score <= 0 && !override) {
+            return;
+        }
+
+        String newAddress = this.getDestinationAccount(this.address);
+        while (newAddress != null) {
+            // Found destination account
+            this.penaltyAddresses.add(newAddress);
+
+            // Run algo for this address, but in "override" mode because it has already been flagged
+            SelfSponsorshipAlgoV1 algoV1 = new SelfSponsorshipAlgoV1(this.repository, newAddress, this.snapshotTimestamp, true);
+            algoV1.run();
+            this.penaltyAddresses.addAll(algoV1.getPenaltyAddresses());
+
+            newAddress = this.getDestinationAccount(newAddress);
+        }
+
+        this.penaltyAddresses.add(this.address);
+
+        if (this.override || this.recentSponsorshipCount < 20) {
+            this.penaltyAddresses.addAll(this.consolidatedAddresses);
+            this.penaltyAddresses.addAll(this.zeroTransactionAddreses);
+        }
+        else {
+            this.penaltyAddresses.addAll(this.sponsees);
+        }
+    }
+
+    private String getDestinationAccount(String address) throws DataException {
+        List<TransactionData> transferPrivsTransactions = fetchTransferPrivsForAddress(address);
+        if (transferPrivsTransactions.isEmpty()) {
+            // No TRANSFER_PRIVS transactions for this address
+            return null;
+        }
+
+        AccountData accountData = this.repository.getAccountRepository().getAccount(address);
+        if (accountData == null) {
+            return null;
+        }
+
+        for (TransactionData transactionData : transferPrivsTransactions) {
+            TransferPrivsTransactionData transferPrivsTransactionData = (TransferPrivsTransactionData) transactionData;
+            if (Arrays.equals(transferPrivsTransactionData.getSenderPublicKey(), accountData.getPublicKey())) {
+                return transferPrivsTransactionData.getRecipient();
+            }
+        }
+
+        return null;
+    }
+
+    private void findConsolidatedRewards() throws DataException {
+        List<String> sponseesThatSentRewards = new ArrayList<>();
+        Map<String, Integer> paymentRecipients = new HashMap<>();
+
+        // Collect outgoing payments of each sponsee
+        for (String sponseeAddress : this.sponsees) {
+
+            // Firstly fetch all payments for address, since the functions below depend on this data
+            this.fetchPaymentsForAddress(sponseeAddress);
+
+            // Check if the address has zero relevant transactions
+            if (this.hasZeroTransactions(sponseeAddress)) {
+                this.zeroTransactionAddreses.add(sponseeAddress);
+            }
+
+            // Get payment recipients
+            List<String> allPaymentRecipients = this.fetchOutgoingPaymentRecipientsForAddress(sponseeAddress);
+            if (allPaymentRecipients.isEmpty()) {
+                continue;
+            }
+            sponseesThatSentRewards.add(sponseeAddress);
+
+            List<String> addressesPaidByThisSponsee = new ArrayList<>();
+            for (String paymentRecipient : allPaymentRecipients) {
+                if (addressesPaidByThisSponsee.contains(paymentRecipient)) {
+                    // We already tracked this association - don't allow multiple to stack up
+                    continue;
+                }
+                addressesPaidByThisSponsee.add(paymentRecipient);
+
+                // Increment count for this recipient, or initialize to 1 if not present
+                if (paymentRecipients.computeIfPresent(paymentRecipient, (k, v) -> v + 1) == null) {
+                    paymentRecipients.put(paymentRecipient, 1);
+                }
+            }
+
+        }
+
+        // Exclude addresses with a low number of payments
+        Map<String, Integer> filteredPaymentRecipients = paymentRecipients.entrySet().stream()
+                .filter(p -> p.getValue() != null && p.getValue() >= 10)
+                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+
+        // Now check how many sponsees have sent to this subset of addresses
+        Map<String, Integer> sponseesThatConsolidatedRewards = new HashMap<>();
+        for (String sponseeAddress : sponseesThatSentRewards) {
+            List<String> allPaymentRecipients = this.fetchOutgoingPaymentRecipientsForAddress(sponseeAddress);
+            // Remove any that aren't to one of the flagged recipients (i.e. consolidation)
+            allPaymentRecipients.removeIf(r -> !filteredPaymentRecipients.containsKey(r));
+
+            int count = allPaymentRecipients.size();
+            if (count == 0) {
+                continue;
+            }
+            if (sponseesThatConsolidatedRewards.computeIfPresent(sponseeAddress, (k, v) -> v + count) == null) {
+                sponseesThatConsolidatedRewards.put(sponseeAddress, count);
+            }
+        }
+
+        // Remove sponsees that have only sent a low number of payments to the filtered addresses
+        Map<String, Integer> filteredSponseesThatConsolidatedRewards = sponseesThatConsolidatedRewards.entrySet().stream()
+                .filter(p -> p.getValue() != null && p.getValue() >= 2)
+                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+
+        this.consolidationCount = sponseesThatConsolidatedRewards.size();
+        this.consolidatedAddresses = new LinkedHashSet<>(filteredSponseesThatConsolidatedRewards.keySet());
+        this.suspiciousCount = this.consolidationCount + this.zeroTransactionAddreses.size();
+        this.suspiciousPercent = (int)(this.suspiciousCount / (float) this.sponsees.size() * 100);
+    }
+
+    private void findBulkIssuance() {
+        Long lastTimestamp = null;
+        for (RewardShareTransactionData rewardShareTransactionData : sponsorshipRewardShares) {
+            long timestamp = rewardShareTransactionData.getTimestamp();
+            if (timestamp >= this.snapshotTimestamp) {
+                continue;
+            }
+
+            if (lastTimestamp != null) {
+                if (timestamp - lastTimestamp < 3*60*1000L) {
+                    this.bulkIssuanceCount++;
+                }
+            }
+            lastTimestamp = timestamp;
+        }
+    }
+
+    private void findRegisteredNameCount() throws DataException {
+        int registeredNameCount = 0;
+        for (String sponseeAddress : sponsees) {
+            List<NameData> names = repository.getNameRepository().getNamesByOwner(sponseeAddress);
+            for (NameData name : names) {
+                if (name.getRegistered() < this.snapshotTimestamp) {
+                    registeredNameCount++;
+                    break;
+                }
+            }
+        }
+        this.registeredNameCount = registeredNameCount;
+    }
+
+    private void findRecentSponsorshipCount() {
+        final long referenceTimestamp = this.snapshotTimestamp - (365 * 24 * 60 * 60 * 1000L);
+        int recentSponsorshipCount = 0;
+        for (RewardShareTransactionData rewardShare : sponsorshipRewardShares) {
+            if (rewardShare.getTimestamp() >= referenceTimestamp) {
+                recentSponsorshipCount++;
+            }
+        }
+        this.recentSponsorshipCount = recentSponsorshipCount;
+    }
+
+    private int calculateScore() {
+        final int suspiciousMultiplier = (this.suspiciousCount >= 100) ? this.suspiciousPercent : 1;
+        final int nameMultiplier = (this.sponsees.size() >= 50 && this.registeredNameCount == 0) ? 2 : 1;
+        final int consolidationMultiplier = Math.max(this.consolidationCount, 1);
+        final int bulkIssuanceMultiplier = Math.max(this.bulkIssuanceCount / 2, 1);
+        final int offset = 9;
+        return suspiciousMultiplier * nameMultiplier * consolidationMultiplier * bulkIssuanceMultiplier - offset;
+    }
+
+    private void fetchSponsorshipRewardShares() throws DataException {
+        List<RewardShareTransactionData> sponsorshipRewardShares = new ArrayList<>();
+
+        // Define relevant transactions
+        List<TransactionType> txTypes = List.of(TransactionType.REWARD_SHARE);
+        List<TransactionData> transactionDataList = fetchTransactions(repository, txTypes, this.address, false);
+
+        for (TransactionData transactionData : transactionDataList) {
+            if (transactionData.getType() != TransactionType.REWARD_SHARE) {
+                continue;
+            }
+
+            RewardShareTransactionData rewardShareTransactionData = (RewardShareTransactionData) transactionData;
+
+            // Skip removals
+            if (rewardShareTransactionData.getSharePercent() < 0) {
+                continue;
+            }
+
+            // Skip if not sponsored by this account
+            if (!Arrays.equals(rewardShareTransactionData.getCreatorPublicKey(), accountData.getPublicKey())) {
+                continue;
+            }
+
+            // Skip self shares
+            if (Objects.equals(rewardShareTransactionData.getRecipient(), this.address)) {
+                continue;
+            }
+
+            boolean duplicateFound = false;
+            for (RewardShareTransactionData existingRewardShare : sponsorshipRewardShares) {
+                if (Objects.equals(existingRewardShare.getRecipient(), rewardShareTransactionData.getRecipient())) {
+                    // Duplicate
+                    duplicateFound = true;
+                    break;
+                }
+            }
+            if (!duplicateFound) {
+                sponsorshipRewardShares.add(rewardShareTransactionData);
+                this.sponsees.add(rewardShareTransactionData.getRecipient());
+            }
+        }
+
+        this.sponsorshipRewardShares = sponsorshipRewardShares;
+    }
+
+    private List<TransactionData> fetchTransferPrivsForAddress(String address) throws DataException {
+        return fetchTransactions(repository,
+                List.of(TransactionType.TRANSFER_PRIVS),
+                address, true);
+    }
+
+    private void fetchPaymentsForAddress(String address) throws DataException {
+        List<TransactionData> payments = fetchTransactions(repository,
+                Arrays.asList(TransactionType.PAYMENT, TransactionType.TRANSFER_ASSET),
+                address, false);
+        this.paymentsByAddress.put(address, payments);
+    }
+
+    private List<String> fetchOutgoingPaymentRecipientsForAddress(String address) {
+        List<String> outgoingPaymentRecipients = new ArrayList<>();
+
+        List<TransactionData> transactionDataList = this.paymentsByAddress.get(address);
+        if (transactionDataList == null) transactionDataList = new ArrayList<>();
+        transactionDataList.removeIf(t -> t.getTimestamp() >= this.snapshotTimestamp);
+        for (TransactionData transactionData : transactionDataList) {
+            switch (transactionData.getType()) {
+
+                case PAYMENT:
+                    PaymentTransactionData paymentTransactionData = (PaymentTransactionData) transactionData;
+                    if (!Objects.equals(paymentTransactionData.getRecipient(), address)) {
+                        // Outgoing payment from this account
+                        outgoingPaymentRecipients.add(paymentTransactionData.getRecipient());
+                    }
+                    break;
+
+                case TRANSFER_ASSET:
+                    TransferAssetTransactionData transferAssetTransactionData = (TransferAssetTransactionData) transactionData;
+                    if (transferAssetTransactionData.getAssetId() == Asset.QORT) {
+                        if (!Objects.equals(transferAssetTransactionData.getRecipient(), address)) {
+                            // Outgoing payment from this account
+                            outgoingPaymentRecipients.add(transferAssetTransactionData.getRecipient());
+                        }
+                    }
+                    break;
+
+                default:
+                    break;
+            }
+        }
+
+        return outgoingPaymentRecipients;
+    }
+
+    private boolean hasZeroTransactions(String address) {
+        List<TransactionData> transactionDataList = this.paymentsByAddress.get(address);
+        if (transactionDataList == null) {
+            return true;
+        }
+        transactionDataList.removeIf(t -> t.getTimestamp() >= this.snapshotTimestamp);
+        return transactionDataList.size() == 0;
+    }
+
+    private static List<TransactionData> fetchTransactions(Repository repository, List<TransactionType> txTypes, String address, boolean reverse) throws DataException {
+        // Fetch all relevant transactions for this account
+        List<byte[]> signatures = repository.getTransactionRepository()
+                .getSignaturesMatchingCriteria(null, null, null, txTypes,
+                        null, null, address, TransactionsResource.ConfirmationStatus.CONFIRMED,
+                        null, null, reverse);
+
+        List<TransactionData> transactionDataList = new ArrayList<>();
+
+        for (byte[] signature : signatures) {
+            // Fetch transaction data
+            TransactionData transactionData = repository.getTransactionRepository().fromSignature(signature);
+            if (transactionData == null) {
+                continue;
+            }
+            transactionDataList.add(transactionData);
+        }
+
+        return transactionDataList;
+    }
+
+}

src/main/java/org/qortal/api/model/AccountPenaltyStats.java

@@ -0,0 +1,56 @@
+package org.qortal.api.model;
+
+import org.qortal.block.SelfSponsorshipAlgoV1Block;
+import org.qortal.data.account.AccountData;
+import org.qortal.data.naming.NameData;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.XmlElement;
+import java.util.ArrayList;
+import java.util.List;
+
+@XmlAccessorType(XmlAccessType.FIELD)
+public class AccountPenaltyStats {
+
+	public Integer totalPenalties;
+	public Integer maxPenalty;
+	public Integer minPenalty;
+	public String penaltyHash;
+
+	protected AccountPenaltyStats() {
+	}
+
+	public AccountPenaltyStats(Integer totalPenalties, Integer maxPenalty, Integer minPenalty, String penaltyHash) {
+		this.totalPenalties = totalPenalties;
+		this.maxPenalty = maxPenalty;
+		this.minPenalty = minPenalty;
+		this.penaltyHash = penaltyHash;
+	}
+
+	public static AccountPenaltyStats fromAccounts(List<AccountData> accounts) {
+		int totalPenalties = 0;
+		Integer maxPenalty = null;
+		Integer minPenalty = null;
+
+		List<String> addresses = new ArrayList<>();
+		for (AccountData accountData : accounts) {
+			int penalty = accountData.getBlocksMintedPenalty();
+			addresses.add(accountData.getAddress());
+			totalPenalties++;
+
+			// Penalties are expressed as a negative number, so the min and the max are reversed here
+			if (maxPenalty == null || penalty < maxPenalty) maxPenalty = penalty;
+			if (minPenalty == null || penalty > minPenalty) minPenalty = penalty;
+		}
+
+		String penaltyHash = SelfSponsorshipAlgoV1Block.getHash(addresses);
+		return new AccountPenaltyStats(totalPenalties, maxPenalty, minPenalty, penaltyHash);
+	}
+
+
+	@Override
+	public String toString() {
+		return String.format("totalPenalties: %d, maxPenalty: %d, minPenalty: %d, penaltyHash: %s", totalPenalties, maxPenalty, minPenalty, penaltyHash == null ? "null" : penaltyHash);
+	}
+}

src/main/java/org/qortal/api/resource/AddressesResource.java

@@ -14,6 +14,7 @@ import java.math.BigDecimal;
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
+import java.util.stream.Collectors;
 
 import javax.servlet.http.HttpServletRequest;
 import javax.ws.rs.*;
@@ -27,6 +28,7 @@ import org.qortal.api.ApiErrors;
 import org.qortal.api.ApiException;
 import org.qortal.api.ApiExceptionFactory;
 import org.qortal.api.Security;
+import org.qortal.api.model.AccountPenaltyStats;
 import org.qortal.api.model.ApiOnlineAccount;
 import org.qortal.api.model.RewardShareKeyRequest;
 import org.qortal.asset.Asset;
@@ -34,6 +36,7 @@ import org.qortal.controller.LiteNode;
 import org.qortal.controller.OnlineAccountsManager;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.account.AccountData;
+import org.qortal.data.account.AccountPenaltyData;
 import org.qortal.data.account.RewardShareData;
 import org.qortal.data.network.OnlineAccountData;
 import org.qortal.data.network.OnlineAccountLevel;
@@ -471,6 +474,54 @@ public class AddressesResource {
 		}
 	}
 
+	@GET
+	@Path("/penalties")
+	@Operation(
+			summary = "Get addresses with penalties",
+			description = "Returns a list of accounts with a blocksMintedPenalty",
+			responses = {
+					@ApiResponse(
+							description = "accounts with penalties",
+							content = @Content(mediaType = MediaType.APPLICATION_JSON, array = @ArraySchema(schema = @Schema(implementation = AccountPenaltyData.class)))
+					)
+			}
+	)
+	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.REPOSITORY_ISSUE})
+	public List<AccountPenaltyData> getAccountsWithPenalties() {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+
+			List<AccountData> accounts = repository.getAccountRepository().getPenaltyAccounts();
+			List<AccountPenaltyData> penalties = accounts.stream().map(a -> new AccountPenaltyData(a.getAddress(), a.getBlocksMintedPenalty())).collect(Collectors.toList());
+
+			return penalties;
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@GET
+	@Path("/penalties/stats")
+	@Operation(
+			summary = "Get stats about current penalties",
+			responses = {
+					@ApiResponse(
+							description = "aggregated stats about accounts with penalties",
+							content = @Content(mediaType = MediaType.APPLICATION_JSON, array = @ArraySchema(schema = @Schema(implementation = AccountPenaltyStats.class)))
+					)
+			}
+	)
+	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.REPOSITORY_ISSUE})
+	public AccountPenaltyStats getPenaltyStats() {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+
+			List<AccountData> accounts = repository.getAccountRepository().getPenaltyAccounts();
+			return AccountPenaltyStats.fromAccounts(accounts);
+
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
 	@POST
 	@Path("/publicize")
 	@Operation(

src/main/java/org/qortal/arbitrary/misc/Service.java

@@ -1,16 +1,18 @@
 package org.qortal.arbitrary.misc;
 
+import org.apache.commons.io.FilenameUtils;
 import org.json.JSONObject;
 import org.qortal.arbitrary.ArbitraryDataRenderer;
 import org.qortal.transaction.Transaction;
 import org.qortal.utils.FilesystemUtils;
 
+import java.io.File;
 import java.io.IOException;
 import java.nio.file.Path;
 import java.nio.file.Paths;
-import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 import static java.util.Arrays.stream;
 import static java.util.stream.Collectors.toMap;
@@ -38,6 +40,7 @@ public enum Service {
     GIT_REPOSITORY(300, false, null, null),
     IMAGE(400, true, 10*1024*1024L, null),
     THUMBNAIL(410, true, 500*1024L, null),
+    QCHAT_IMAGE(420, true, 500*1024L, null),
     VIDEO(500, false, null, null),
     AUDIO(600, false, null, null),
     BLOG(700, false, null, null),
@@ -48,7 +51,30 @@ public enum Service {
     PLAYLIST(910, true, null, null),
     APP(1000, false, null, null),
     METADATA(1100, false, null, null),
-    QORTAL_METADATA(1111, true, 10*1024L, Arrays.asList("title", "description", "tags"));
+    GIF_REPOSITORY(1200, true, 25*1024*1024L, null) {
+        @Override
+        public ValidationResult validate(Path path) {
+            // Custom validation function to require .gif files only, and at least 1
+            int gifCount = 0;
+            File[] files = path.toFile().listFiles();
+            if (files != null) {
+                for (File file : files) {
+                    if (file.isDirectory()) {
+                        return ValidationResult.DIRECTORIES_NOT_ALLOWED;
+                    }
+                    String extension = FilenameUtils.getExtension(file.getName()).toLowerCase();
+                    if (!Objects.equals(extension, "gif")) {
+                        return ValidationResult.INVALID_FILE_EXTENSION;
+                    }
+                    gifCount++;
+                }
+            }
+            if (gifCount == 0) {
+                return ValidationResult.MISSING_DATA;
+            }
+            return ValidationResult.OK;
+        }
+    };
 
     public final int value;
     private final boolean requiresValidation;
@@ -114,7 +140,10 @@ public enum Service {
         OK(1),
         MISSING_KEYS(2),
         EXCEEDS_SIZE_LIMIT(3),
-        MISSING_INDEX_FILE(4);
+        MISSING_INDEX_FILE(4),
+        DIRECTORIES_NOT_ALLOWED(5),
+        INVALID_FILE_EXTENSION(6),
+        MISSING_DATA(7);
 
         public final int value;
 

src/main/java/org/qortal/block/Block.java

@@ -136,7 +136,7 @@ public class Block {
 	}
 
 	/** Lazy-instantiated expanded info on block's online accounts. */
-	private static class ExpandedAccount {
+	public static class ExpandedAccount {
 		private final RewardShareData rewardShareData;
 		private final int sharePercent;
 		private final boolean isRecipientAlsoMinter;
@@ -169,6 +169,13 @@ public class Block {
 			}
 		}
 
+		public Account getMintingAccount() {
+			return this.mintingAccount;
+		}
+		public Account getRecipientAccount() {
+			return this.recipientAccount;
+		}
+
 		/**
 		 * Returns share bin for expanded account.
 		 * <p>
@@ -363,15 +370,24 @@ public class Block {
 			return null;
 		}
 
+		int height = parentBlockData.getHeight() + 1;
 		long timestamp = calcTimestamp(parentBlockData, minter.getPublicKey(), minterLevel);
 		long onlineAccountsTimestamp = OnlineAccountsManager.getCurrentOnlineAccountTimestamp();
 
-		// Fetch our list of online accounts
+		// Fetch our list of online accounts, removing any that are missing a nonce
 		List<OnlineAccountData> onlineAccounts = OnlineAccountsManager.getInstance().getOnlineAccounts(onlineAccountsTimestamp);
+		onlineAccounts.removeIf(a -> a.getNonce() == null || a.getNonce() < 0);
 
-		// If mempow is active, remove any legacy accounts that are missing a nonce
-		if (timestamp >= BlockChain.getInstance().getOnlineAccountsMemoryPoWTimestamp()) {
-			onlineAccounts.removeIf(a -> a.getNonce() == null || a.getNonce() < 0);
+		// After feature trigger, remove any online accounts that are level 0
+		if (height >= BlockChain.getInstance().getOnlineAccountMinterLevelValidationHeight()) {
+			onlineAccounts.removeIf(a -> {
+				try {
+					return Account.getRewardShareEffectiveMintingLevel(repository, a.getPublicKey()) == 0;
+				} catch (DataException e) {
+					// Something went wrong, so remove the account
+					return true;
+				}
+			});
 		}
 
 		if (onlineAccounts.isEmpty()) {
@@ -412,29 +428,27 @@ public class Block {
 		// Aggregated, single signature
 		byte[] onlineAccountsSignatures = Qortal25519Extras.aggregateSignatures(signaturesToAggregate);
 
-		// Add nonces to the end of the online accounts signatures if mempow is active
-		if (timestamp >= BlockChain.getInstance().getOnlineAccountsMemoryPoWTimestamp()) {
-			try {
-				// Create ordered list of nonce values
-				List<Integer> nonces = new ArrayList<>();
-				for (int i = 0; i < onlineAccountsCount; ++i) {
-					Integer accountIndex = accountIndexes.get(i);
-					OnlineAccountData onlineAccountData = indexedOnlineAccounts.get(accountIndex);
-					nonces.add(onlineAccountData.getNonce());
-				}
-
-				// Encode the nonces to a byte array
-				byte[] encodedNonces = BlockTransformer.encodeOnlineAccountNonces(nonces);
-
-				// Append the encoded nonces to the encoded online account signatures
-				ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
-				outputStream.write(onlineAccountsSignatures);
-				outputStream.write(encodedNonces);
-				onlineAccountsSignatures = outputStream.toByteArray();
-			}
-			catch (TransformationException | IOException e) {
-				return null;
+		// Add nonces to the end of the online accounts signatures
+		try {
+			// Create ordered list of nonce values
+			List<Integer> nonces = new ArrayList<>();
+			for (int i = 0; i < onlineAccountsCount; ++i) {
+				Integer accountIndex = accountIndexes.get(i);
+				OnlineAccountData onlineAccountData = indexedOnlineAccounts.get(accountIndex);
+				nonces.add(onlineAccountData.getNonce());
 			}
+
+			// Encode the nonces to a byte array
+			byte[] encodedNonces = BlockTransformer.encodeOnlineAccountNonces(nonces);
+
+			// Append the encoded nonces to the encoded online account signatures
+			ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+			outputStream.write(onlineAccountsSignatures);
+			outputStream.write(encodedNonces);
+			onlineAccountsSignatures = outputStream.toByteArray();
+		}
+		catch (TransformationException | IOException e) {
+			return null;
 		}
 
 		byte[] minterSignature = minter.sign(BlockTransformer.getBytesForMinterSignature(parentBlockData,
@@ -442,7 +456,6 @@ public class Block {
 
 		int transactionCount = 0;
 		byte[] transactionsSignature = null;
-		int height = parentBlockData.getHeight() + 1;
 
 		int atCount = 0;
 		long atFees = 0;
@@ -1036,6 +1049,15 @@ public class Block {
 		if (onlineRewardShares == null)
 			return ValidationResult.ONLINE_ACCOUNT_UNKNOWN;
 
+		// After feature trigger, require all online account minters to be greater than level 0
+		if (this.getBlockData().getHeight() >= BlockChain.getInstance().getOnlineAccountMinterLevelValidationHeight()) {
+			List<ExpandedAccount> expandedAccounts = this.getExpandedAccounts();
+			for (ExpandedAccount account : expandedAccounts) {
+				if (account.getMintingAccount().getEffectiveMintingLevel() == 0)
+					return ValidationResult.ONLINE_ACCOUNTS_INVALID;
+			}
+		}
+
 		// If block is past a certain age then we simply assume the signatures were correct
 		long signatureRequirementThreshold = NTP.getTime() - BlockChain.getInstance().getOnlineAccountSignaturesMinLifetime();
 		if (this.blockData.getTimestamp() < signatureRequirementThreshold)
@@ -1047,14 +1069,9 @@ public class Block {
 		final int signaturesLength = Transformer.SIGNATURE_LENGTH;
 		final int noncesLength = onlineRewardShares.size() * Transformer.INT_LENGTH;
 
-		if (this.blockData.getTimestamp() >= BlockChain.getInstance().getOnlineAccountsMemoryPoWTimestamp()) {
-			// We expect nonces to be appended to the online accounts signatures
-			if (this.blockData.getOnlineAccountsSignatures().length != signaturesLength + noncesLength)
-				return ValidationResult.ONLINE_ACCOUNT_SIGNATURES_MALFORMED;
-		} else {
-			if (this.blockData.getOnlineAccountsSignatures().length != signaturesLength)
-				return ValidationResult.ONLINE_ACCOUNT_SIGNATURES_MALFORMED;
-		}
+		// We expect nonces to be appended to the online accounts signatures
+		if (this.blockData.getOnlineAccountsSignatures().length != signaturesLength + noncesLength)
+			return ValidationResult.ONLINE_ACCOUNT_SIGNATURES_MALFORMED;
 
 		// Check signatures
 		long onlineTimestamp = this.blockData.getOnlineAccountsTimestamp();
@@ -1063,32 +1080,33 @@ public class Block {
 		byte[] encodedOnlineAccountSignatures = this.blockData.getOnlineAccountsSignatures();
 
 		// Split online account signatures into signature(s) + nonces, then validate the nonces
-		if (this.blockData.getTimestamp() >= BlockChain.getInstance().getOnlineAccountsMemoryPoWTimestamp()) {
-			byte[] extractedSignatures = BlockTransformer.extract(encodedOnlineAccountSignatures, 0, signaturesLength);
-			byte[] extractedNonces = BlockTransformer.extract(encodedOnlineAccountSignatures, signaturesLength, onlineRewardShares.size() * Transformer.INT_LENGTH);
-			encodedOnlineAccountSignatures = extractedSignatures;
+		byte[] extractedSignatures = BlockTransformer.extract(encodedOnlineAccountSignatures, 0, signaturesLength);
+		byte[] extractedNonces = BlockTransformer.extract(encodedOnlineAccountSignatures, signaturesLength, onlineRewardShares.size() * Transformer.INT_LENGTH);
+		encodedOnlineAccountSignatures = extractedSignatures;
 
-			List<Integer> nonces = BlockTransformer.decodeOnlineAccountNonces(extractedNonces);
+		List<Integer> nonces = BlockTransformer.decodeOnlineAccountNonces(extractedNonces);
 
-			// Build block's view of online accounts (without signatures, as we don't need them here)
-			Set<OnlineAccountData> onlineAccounts = new HashSet<>();
-			for (int i = 0; i < onlineRewardShares.size(); ++i) {
-				Integer nonce = nonces.get(i);
-				byte[] publicKey = onlineRewardShares.get(i).getRewardSharePublicKey();
+		// Build block's view of online accounts (without signatures, as we don't need them here)
+		Set<OnlineAccountData> onlineAccounts = new HashSet<>();
+		for (int i = 0; i < onlineRewardShares.size(); ++i) {
+			Integer nonce = nonces.get(i);
+			byte[] publicKey = onlineRewardShares.get(i).getRewardSharePublicKey();
 
-				OnlineAccountData onlineAccountData = new OnlineAccountData(onlineTimestamp, null, publicKey, nonce);
-				onlineAccounts.add(onlineAccountData);
-			}
-
-			// Remove those already validated & cached by online accounts manager - no need to re-validate them
-			OnlineAccountsManager.getInstance().removeKnown(onlineAccounts, onlineTimestamp);
-
-			// Validate the rest
-			for (OnlineAccountData onlineAccount : onlineAccounts)
-				if (!OnlineAccountsManager.getInstance().verifyMemoryPoW(onlineAccount, this.blockData.getTimestamp()))
-					return ValidationResult.ONLINE_ACCOUNT_NONCE_INCORRECT;
+			OnlineAccountData onlineAccountData = new OnlineAccountData(onlineTimestamp, null, publicKey, nonce);
+			onlineAccounts.add(onlineAccountData);
 		}
 
+		// Remove those already validated & cached by online accounts manager - no need to re-validate them
+		OnlineAccountsManager.getInstance().removeKnown(onlineAccounts, onlineTimestamp);
+
+		// Validate the rest
+		for (OnlineAccountData onlineAccount : onlineAccounts)
+			if (!OnlineAccountsManager.getInstance().verifyMemoryPoW(onlineAccount, null))
+				return ValidationResult.ONLINE_ACCOUNT_NONCE_INCORRECT;
+
+		// Cache the valid online accounts as they will likely be needed for the next block
+		OnlineAccountsManager.getInstance().addBlocksOnlineAccounts(onlineAccounts, onlineTimestamp);
+
 		// Extract online accounts' timestamp signatures from block data. Only one signature if aggregated.
 		List<byte[]> onlineAccountsSignatures = BlockTransformer.decodeTimestampSignatures(encodedOnlineAccountSignatures);
 
@@ -1445,6 +1463,9 @@ public class Block {
 			if (this.blockData.getHeight() == 212937)
 				// Apply fix for block 212937
 				Block212937.processFix(this);
+
+			else if (this.blockData.getHeight() == BlockChain.getInstance().getSelfSponsorshipAlgoV1Height())
+				SelfSponsorshipAlgoV1Block.processAccountPenalties(this);
 		}
 
 		// We're about to (test-)process a batch of transactions,
@@ -1507,7 +1528,7 @@ public class Block {
 			accountData.setBlocksMinted(accountData.getBlocksMinted() + 1);
 			LOGGER.trace(() -> String.format("Block minter %s up to %d minted block%s", accountData.getAddress(), accountData.getBlocksMinted(), (accountData.getBlocksMinted() != 1 ? "s" : "")));
 
-			final int effectiveBlocksMinted = accountData.getBlocksMinted() + accountData.getBlocksMintedAdjustment();
+			final int effectiveBlocksMinted = accountData.getBlocksMinted() + accountData.getBlocksMintedAdjustment() + accountData.getBlocksMintedPenalty();
 
 			for (int newLevel = maximumLevel; newLevel >= 0; --newLevel)
 				if (effectiveBlocksMinted >= cumulativeBlocksByLevel.get(newLevel)) {
@@ -1680,6 +1701,9 @@ public class Block {
 				// Revert fix for block 212937
 				Block212937.orphanFix(this);
 
+			else if (this.blockData.getHeight() == BlockChain.getInstance().getSelfSponsorshipAlgoV1Height())
+				SelfSponsorshipAlgoV1Block.orphanAccountPenalties(this);
+
 			// Block rewards, including transaction fees, removed after transactions undone
 			orphanBlockRewards();
 
@@ -1808,7 +1832,7 @@ public class Block {
 			accountData.setBlocksMinted(accountData.getBlocksMinted() - 1);
 			LOGGER.trace(() -> String.format("Block minter %s down to %d minted block%s", accountData.getAddress(), accountData.getBlocksMinted(), (accountData.getBlocksMinted() != 1 ? "s" : "")));
 
-			final int effectiveBlocksMinted = accountData.getBlocksMinted() + accountData.getBlocksMintedAdjustment();
+			final int effectiveBlocksMinted = accountData.getBlocksMinted() + accountData.getBlocksMintedAdjustment() + accountData.getBlocksMintedPenalty();
 
 			for (int newLevel = maximumLevel; newLevel >= 0; --newLevel)
 				if (effectiveBlocksMinted >= cumulativeBlocksByLevel.get(newLevel)) {

src/main/java/org/qortal/block/BlockChain.java

@@ -73,7 +73,10 @@ public class BlockChain {
 		calcChainWeightTimestamp,
 		transactionV5Timestamp,
 		transactionV6Timestamp,
-		disableReferenceTimestamp;
+		disableReferenceTimestamp,
+		increaseOnlineAccountsDifficultyTimestamp,
+		onlineAccountMinterLevelValidationHeight,
+		selfSponsorshipAlgoV1Height;
 	}
 
 	// Custom transaction fees
@@ -195,9 +198,8 @@ public class BlockChain {
 	 * featureTriggers because unit tests need to set this value via Reflection. */
 	private long onlineAccountsModulusV2Timestamp;
 
-	/** Feature trigger timestamp for online accounts mempow verification. Can't use featureTriggers
-	 * because unit tests need to set this value via Reflection. */
-	private long onlineAccountsMemoryPoWTimestamp;
+	/** Snapshot timestamp for self sponsorship algo V1 */
+	private long selfSponsorshipAlgoV1SnapshotTimestamp;
 
 	/** Max reward shares by block height */
 	public static class MaxRewardSharesByTimestamp {
@@ -359,8 +361,9 @@ public class BlockChain {
 		return this.onlineAccountsModulusV2Timestamp;
 	}
 
-	public long getOnlineAccountsMemoryPoWTimestamp() {
-		return this.onlineAccountsMemoryPoWTimestamp;
+	// Self sponsorship algo
+	public long getSelfSponsorshipAlgoV1SnapshotTimestamp() {
+		return this.selfSponsorshipAlgoV1SnapshotTimestamp;
 	}
 
 	/** Returns true if approval-needing transaction types require a txGroupId other than NO_GROUP. */
@@ -486,6 +489,18 @@ public class BlockChain {
 		return this.featureTriggers.get(FeatureTrigger.disableReferenceTimestamp.name()).longValue();
 	}
 
+	public long getIncreaseOnlineAccountsDifficultyTimestamp() {
+		return this.featureTriggers.get(FeatureTrigger.increaseOnlineAccountsDifficultyTimestamp.name()).longValue();
+	}
+
+	public int getSelfSponsorshipAlgoV1Height() {
+		return this.featureTriggers.get(FeatureTrigger.selfSponsorshipAlgoV1Height.name()).intValue();
+	}
+
+	public long getOnlineAccountMinterLevelValidationHeight() {
+		return this.featureTriggers.get(FeatureTrigger.onlineAccountMinterLevelValidationHeight.name()).intValue();
+	}
+
 
 	// More complex getters for aspects that change by height or timestamp
 

src/main/java/org/qortal/block/SelfSponsorshipAlgoV1Block.java

@@ -0,0 +1,133 @@
+package org.qortal.block;
+
+import org.apache.commons.lang3.StringUtils;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.account.SelfSponsorshipAlgoV1;
+import org.qortal.api.model.AccountPenaltyStats;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.account.AccountData;
+import org.qortal.data.account.AccountPenaltyData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.utils.Base58;
+
+import java.nio.charset.StandardCharsets;
+import java.util.*;
+import java.util.stream.Collectors;
+
+/**
+ * Self Sponsorship AlgoV1 Block
+ * <p>
+ * Selected block for the initial run on the "self sponsorship detection algorithm"
+ */
+public final class SelfSponsorshipAlgoV1Block {
+
+	private static final Logger LOGGER = LogManager.getLogger(SelfSponsorshipAlgoV1Block.class);
+
+
+	private SelfSponsorshipAlgoV1Block() {
+		/* Do not instantiate */
+	}
+
+	public static void processAccountPenalties(Block block) throws DataException {
+		LOGGER.info("Running algo for block processing - this will take a while...");
+		logPenaltyStats(block.repository);
+		long startTime = System.currentTimeMillis();
+		Set<AccountPenaltyData> penalties = getAccountPenalties(block.repository, -5000000);
+		block.repository.getAccountRepository().updateBlocksMintedPenalties(penalties);
+		long totalTime = System.currentTimeMillis() - startTime;
+		String hash = getHash(penalties.stream().map(p -> p.getAddress()).collect(Collectors.toList()));
+		LOGGER.info("{} penalty addresses processed (hash: {}). Total time taken: {} seconds", penalties.size(), hash, (int)(totalTime / 1000.0f));
+		logPenaltyStats(block.repository);
+
+		int updatedCount = updateAccountLevels(block.repository, penalties);
+		LOGGER.info("Account levels updated for {} penalty addresses", updatedCount);
+	}
+
+	public static void orphanAccountPenalties(Block block) throws DataException {
+		LOGGER.info("Running algo for block orphaning - this will take a while...");
+		logPenaltyStats(block.repository);
+		long startTime = System.currentTimeMillis();
+		Set<AccountPenaltyData> penalties = getAccountPenalties(block.repository, 5000000);
+		block.repository.getAccountRepository().updateBlocksMintedPenalties(penalties);
+		long totalTime = System.currentTimeMillis() - startTime;
+		String hash = getHash(penalties.stream().map(p -> p.getAddress()).collect(Collectors.toList()));
+		LOGGER.info("{} penalty addresses orphaned (hash: {}). Total time taken: {} seconds", penalties.size(), hash, (int)(totalTime / 1000.0f));
+		logPenaltyStats(block.repository);
+
+		int updatedCount = updateAccountLevels(block.repository, penalties);
+		LOGGER.info("Account levels updated for {} penalty addresses", updatedCount);
+	}
+
+	public static Set<AccountPenaltyData> getAccountPenalties(Repository repository, int penalty) throws DataException {
+		final long snapshotTimestamp = BlockChain.getInstance().getSelfSponsorshipAlgoV1SnapshotTimestamp();
+		Set<AccountPenaltyData> penalties = new LinkedHashSet<>();
+		List<String> addresses = repository.getTransactionRepository().getConfirmedRewardShareCreatorsExcludingSelfShares();
+		for (String address : addresses) {
+			//System.out.println(String.format("address: %s", address));
+			SelfSponsorshipAlgoV1 selfSponsorshipAlgoV1 = new SelfSponsorshipAlgoV1(repository, address, snapshotTimestamp, false);
+			selfSponsorshipAlgoV1.run();
+			//System.out.println(String.format("Penalty addresses: %d", selfSponsorshipAlgoV1.getPenaltyAddresses().size()));
+
+			for (String penaltyAddress : selfSponsorshipAlgoV1.getPenaltyAddresses()) {
+				penalties.add(new AccountPenaltyData(penaltyAddress, penalty));
+			}
+		}
+		return penalties;
+	}
+
+	private static int updateAccountLevels(Repository repository, Set<AccountPenaltyData> accountPenalties) throws DataException {
+		final List<Integer> cumulativeBlocksByLevel = BlockChain.getInstance().getCumulativeBlocksByLevel();
+		final int maximumLevel = cumulativeBlocksByLevel.size() - 1;
+
+		int updatedCount = 0;
+
+		for (AccountPenaltyData penaltyData : accountPenalties) {
+			AccountData accountData = repository.getAccountRepository().getAccount(penaltyData.getAddress());
+			final int effectiveBlocksMinted = accountData.getBlocksMinted() + accountData.getBlocksMintedAdjustment() + accountData.getBlocksMintedPenalty();
+
+			// Shortcut for penalties
+			if (effectiveBlocksMinted < 0) {
+				accountData.setLevel(0);
+				repository.getAccountRepository().setLevel(accountData);
+				updatedCount++;
+				LOGGER.trace(() -> String.format("Block minter %s dropped to level %d", accountData.getAddress(), accountData.getLevel()));
+				continue;
+			}
+
+			for (int newLevel = maximumLevel; newLevel >= 0; --newLevel) {
+				if (effectiveBlocksMinted >= cumulativeBlocksByLevel.get(newLevel)) {
+					accountData.setLevel(newLevel);
+					repository.getAccountRepository().setLevel(accountData);
+					updatedCount++;
+					LOGGER.trace(() -> String.format("Block minter %s increased to level %d", accountData.getAddress(), accountData.getLevel()));
+					break;
+				}
+			}
+		}
+
+		return updatedCount;
+	}
+
+	private static void logPenaltyStats(Repository repository) {
+		try {
+			LOGGER.info(getPenaltyStats(repository));
+
+		} catch (DataException e) {}
+	}
+
+	private static AccountPenaltyStats getPenaltyStats(Repository repository) throws DataException {
+		List<AccountData> accounts = repository.getAccountRepository().getPenaltyAccounts();
+		return AccountPenaltyStats.fromAccounts(accounts);
+	}
+
+	public static String getHash(List<String> penaltyAddresses) {
+		if (penaltyAddresses == null || penaltyAddresses.isEmpty()) {
+			return null;
+		}
+		Collections.sort(penaltyAddresses);
+		return Base58.encode(Crypto.digest(StringUtils.join(penaltyAddresses).getBytes(StandardCharsets.UTF_8)));
+	}
+
+}

src/main/java/org/qortal/controller/BlockMinter.java

@@ -26,9 +26,6 @@ import org.qortal.data.block.CommonBlockData;
 import org.qortal.data.transaction.TransactionData;
 import org.qortal.network.Network;
 import org.qortal.network.Peer;
-import org.qortal.network.message.BlockSummariesV2Message;
-import org.qortal.network.message.HeightV2Message;
-import org.qortal.network.message.Message;
 import org.qortal.repository.BlockRepository;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
@@ -38,6 +35,8 @@ import org.qortal.transaction.Transaction;
 import org.qortal.utils.Base58;
 import org.qortal.utils.NTP;
 
+import static org.junit.Assert.assertNotNull;
+
 // Minting new blocks
 
 public class BlockMinter extends Thread {
@@ -93,6 +92,8 @@ public class BlockMinter extends Thread {
 
 		List<Block> newBlocks = new ArrayList<>();
 
+		final boolean isSingleNodeTestnet = Settings.getInstance().isSingleNodeTestnet();
+
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			// Going to need this a lot...
 			BlockRepository blockRepository = repository.getBlockRepository();
@@ -111,8 +112,9 @@ public class BlockMinter extends Thread {
 					// Free up any repository locks
 					repository.discardChanges();
 
-					// Sleep for a while
-					Thread.sleep(1000);
+					// Sleep for a while.
+					// It's faster on single node testnets, to allow lots of blocks to be minted quickly.
+					Thread.sleep(isSingleNodeTestnet ? 50 : 1000);
 
 					isMintingPossible = false;
 
@@ -223,9 +225,10 @@ public class BlockMinter extends Thread {
 					List<PrivateKeyAccount> newBlocksMintingAccounts = mintingAccountsData.stream().map(accountData -> new PrivateKeyAccount(repository, accountData.getPrivateKey())).collect(Collectors.toList());
 
 					// We might need to sit the next block out, if one of our minting accounts signed the previous one
+					// Skip this check for single node testnets, since they definitely need to mint every block
 					byte[] previousBlockMinter = previousBlockData.getMinterPublicKey();
 					boolean mintedLastBlock = mintingAccountsData.stream().anyMatch(mintingAccount -> Arrays.equals(mintingAccount.getPublicKey(), previousBlockMinter));
-					if (mintedLastBlock) {
+					if (mintedLastBlock && !isSingleNodeTestnet) {
 						LOGGER.trace(String.format("One of our keys signed the last block, so we won't sign the next one"));
 						continue;
 					}
@@ -244,7 +247,7 @@ public class BlockMinter extends Thread {
 							Block newBlock = Block.mint(repository, previousBlockData, mintingAccount);
 							if (newBlock == null) {
 								// For some reason we can't mint right now
-								moderatedLog(() -> LOGGER.error("Couldn't build a to-be-minted block"));
+								moderatedLog(() -> LOGGER.info("Couldn't build a to-be-minted block"));
 								continue;
 							}
 
@@ -507,6 +510,21 @@ public class BlockMinter extends Thread {
 
 		PrivateKeyAccount mintingAccount = mintingAndOnlineAccounts[0];
 
+		Block block = mintTestingBlockRetainingTimestamps(repository, mintingAccount);
+		assertNotNull("Minted block must not be null", block);
+
+		return block;
+	}
+
+	public static Block mintTestingBlockUnvalidated(Repository repository, PrivateKeyAccount... mintingAndOnlineAccounts) throws DataException {
+		if (!BlockChain.getInstance().isTestChain())
+			throw new DataException("Ignoring attempt to mint testing block for non-test chain!");
+
+		// Ensure mintingAccount is 'online' so blocks can be minted
+		OnlineAccountsManager.getInstance().ensureTestingAccountsOnline(mintingAndOnlineAccounts);
+
+		PrivateKeyAccount mintingAccount = mintingAndOnlineAccounts[0];
+
 		return mintTestingBlockRetainingTimestamps(repository, mintingAccount);
 	}
 
@@ -514,6 +532,8 @@ public class BlockMinter extends Thread {
 		BlockData previousBlockData = repository.getBlockRepository().getLastBlock();
 
 		Block newBlock = Block.mint(repository, previousBlockData, mintingAccount);
+		if (newBlock == null)
+			return null;
 
 		// Make sure we're the only thread modifying the blockchain
 		ReentrantLock blockchainLock = Controller.getInstance().getBlockchainLock();

src/main/java/org/qortal/controller/Controller.java

@@ -29,6 +29,7 @@ import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.bouncycastle.jce.provider.BouncyCastleProvider;
 import org.bouncycastle.jsse.provider.BouncyCastleJsseProvider;
+import org.qortal.account.Account;
 import org.qortal.api.ApiService;
 import org.qortal.api.DomainMapService;
 import org.qortal.api.GatewayService;
@@ -756,6 +757,18 @@ public class Controller extends Thread {
 		return peer.isAtLeastVersion(minPeerVersion) == false;
 	};
 
+	public static final Predicate<Peer> hasInvalidSigner = peer -> {
+		final BlockSummaryData peerChainTipData = peer.getChainTipData();
+		if (peerChainTipData == null)
+			return true;
+
+		try (Repository repository = RepositoryManager.getRepository()) {
+			return Account.getRewardShareEffectiveMintingLevel(repository, peerChainTipData.getMinterPublicKey()) == 0;
+		} catch (DataException e) {
+			return true;
+		}
+	};
+
 	private long getRandomRepositoryMaintenanceInterval() {
 		final long minInterval = Settings.getInstance().getRepositoryMaintenanceMinInterval();
 		final long maxInterval = Settings.getInstance().getRepositoryMaintenanceMaxInterval();
@@ -838,6 +851,12 @@ public class Controller extends Thread {
 		String tooltip = String.format("%s - %d %s", actionText, numberOfPeers, connectionsText);
 		if (!Settings.getInstance().isLite()) {
 			tooltip = tooltip.concat(String.format(" - %s %d", heightText, height));
+
+			final Integer blocksRemaining = Synchronizer.getInstance().getBlocksRemaining();
+			if (blocksRemaining != null && blocksRemaining > 0) {
+				String blocksRemainingText = Translator.INSTANCE.translate("SysTray", "BLOCKS_REMAINING");
+				tooltip = tooltip.concat(String.format(" - %d %s", blocksRemaining, blocksRemainingText));
+			}
 		}
 		tooltip = tooltip.concat(String.format("\n%s: %s", Translator.INSTANCE.translate("SysTray", "BUILD_VERSION"), this.buildVersion));
 		SysTray.getInstance().setToolTipText(tooltip);
@@ -1610,7 +1629,7 @@ public class Controller extends Thread {
 			 * having been passed upwards from Peer to Network to Controller.
 			 * Hence, these are NOT simple "here's my chain tip" broadcasts from other peers.
 			 */
-			LOGGER.info("Discarding late {} message with ID {} from {}", message.getType().name(), message.getId(), peer);
+			LOGGER.debug("Discarding late {} message with ID {} from {}", message.getType().name(), message.getId(), peer);
 			return;
 		}
 
@@ -1872,6 +1891,10 @@ public class Controller extends Thread {
 		if (latestBlockData == null || latestBlockData.getTimestamp() < minLatestBlockTimestamp)
 			return false;
 
+		if (Settings.getInstance().isSingleNodeTestnet())
+			// Single node testnets won't have peers, so we can assume up to date from this point
+			return true;
+
 		// Needs a mutable copy of the unmodifiableList
 		List<Peer> peers = new ArrayList<>(Network.getInstance().getImmutableHandshakedPeers());
 		if (peers == null)

src/main/java/org/qortal/controller/OnlineAccountsManager.java

@@ -64,9 +64,19 @@ public class OnlineAccountsManager {
 
     private static final long ONLINE_ACCOUNTS_COMPUTE_INITIAL_SLEEP_INTERVAL = 30 * 1000L; // ms
 
-    // MemoryPoW
-    public final int POW_BUFFER_SIZE = 1 * 1024 * 1024; // bytes
-    public int POW_DIFFICULTY = 18; // leading zero bits
+    // MemoryPoW - mainnet
+    public static final int POW_BUFFER_SIZE = 1 * 1024 * 1024; // bytes
+    public static final int POW_DIFFICULTY_V1 = 18; // leading zero bits
+    public static final int POW_DIFFICULTY_V2 = 19; // leading zero bits
+
+    // MemoryPoW - testnet
+    public static final int POW_BUFFER_SIZE_TESTNET = 1 * 1024 * 1024; // bytes
+    public static final int POW_DIFFICULTY_TESTNET = 5; // leading zero bits
+
+    // IMPORTANT: if we ever need to dynamically modify the buffer size using a feature trigger, the
+    // pre-allocated buffer below will NOT work, and we should instead use a dynamically allocated
+    // one for the transition period.
+    private static long[] POW_VERIFY_WORK_BUFFER = new long[getPoWBufferSize() / 8];
 
     private final ScheduledExecutorService executor = Executors.newScheduledThreadPool(4, new NamedThreadFactory("OnlineAccounts"));
     private volatile boolean isStopping = false;
@@ -112,6 +122,23 @@ public class OnlineAccountsManager {
         return (timestamp / getOnlineTimestampModulus()) * getOnlineTimestampModulus();
     }
 
+    private static int getPoWBufferSize() {
+        if (Settings.getInstance().isTestNet())
+            return POW_BUFFER_SIZE_TESTNET;
+
+        return POW_BUFFER_SIZE;
+    }
+
+    private static int getPoWDifficulty(long timestamp) {
+        if (Settings.getInstance().isTestNet())
+            return POW_DIFFICULTY_TESTNET;
+
+        if (timestamp >= BlockChain.getInstance().getIncreaseOnlineAccountsDifficultyTimestamp())
+            return POW_DIFFICULTY_V2;
+
+        return POW_DIFFICULTY_V1;
+    }
+
     private OnlineAccountsManager() {
     }
 
@@ -156,7 +183,6 @@ public class OnlineAccountsManager {
             return;
 
         byte[] timestampBytes = Longs.toByteArray(onlineAccountsTimestamp);
-        final boolean mempowActive = onlineAccountsTimestamp >= BlockChain.getInstance().getOnlineAccountsMemoryPoWTimestamp();
 
         Set<OnlineAccountData> replacementAccounts = new HashSet<>();
         for (PrivateKeyAccount onlineAccount : onlineAccounts) {
@@ -165,7 +191,7 @@ public class OnlineAccountsManager {
             byte[] signature = Qortal25519Extras.signForAggregation(onlineAccount.getPrivateKey(), timestampBytes);
             byte[] publicKey = onlineAccount.getPublicKey();
 
-            Integer nonce = mempowActive ? new Random().nextInt(500000) : null;
+            Integer nonce = new Random().nextInt(500000);
 
             OnlineAccountData ourOnlineAccountData = new OnlineAccountData(onlineAccountsTimestamp, signature, publicKey, nonce);
             replacementAccounts.add(ourOnlineAccountData);
@@ -192,8 +218,8 @@ public class OnlineAccountsManager {
                     return;
 
                 // Skip this account if it's already validated
-                Set<OnlineAccountData> onlineAccounts = this.currentOnlineAccounts.computeIfAbsent(onlineAccountData.getTimestamp(), k -> ConcurrentHashMap.newKeySet());
-                if (onlineAccounts.contains(onlineAccountData)) {
+                Set<OnlineAccountData> onlineAccounts = this.currentOnlineAccounts.get(onlineAccountData.getTimestamp());
+                if (onlineAccounts != null && onlineAccounts.contains(onlineAccountData)) {
                     // We have already validated this online account
                     onlineAccountsImportQueue.remove(onlineAccountData);
                     continue;
@@ -214,8 +240,8 @@ public class OnlineAccountsManager {
             if (!onlineAccountsToAdd.isEmpty()) {
                 LOGGER.debug("Merging {} validated online accounts from import queue", onlineAccountsToAdd.size());
                 addAccounts(onlineAccountsToAdd);
-                onlineAccountsImportQueue.removeAll(onlineAccountsToRemove);
             }
+            onlineAccountsImportQueue.removeAll(onlineAccountsToRemove);
         }
     }
 
@@ -321,13 +347,10 @@ public class OnlineAccountsManager {
             return false;
         }
 
-        // Validate mempow if feature trigger is active (or if online account's timestamp is past the trigger timestamp)
-        long memoryPoWStartTimestamp = BlockChain.getInstance().getOnlineAccountsMemoryPoWTimestamp();
-        if (now >= memoryPoWStartTimestamp || onlineAccountTimestamp >= memoryPoWStartTimestamp) {
-            if (!getInstance().verifyMemoryPoW(onlineAccountData, now)) {
-                LOGGER.trace(() -> String.format("Rejecting online reward-share for account %s due to invalid PoW nonce", mintingAccount.getAddress()));
-                return false;
-            }
+        // Validate mempow
+        if (!getInstance().verifyMemoryPoW(onlineAccountData, POW_VERIFY_WORK_BUFFER)) {
+            LOGGER.trace(() -> String.format("Rejecting online reward-share for account %s due to invalid PoW nonce", mintingAccount.getAddress()));
+            return false;
         }
 
         return true;
@@ -471,12 +494,10 @@ public class OnlineAccountsManager {
 
         // 'next' timestamp (prioritize this as it's the most important, if mempow active)
         final long nextOnlineAccountsTimestamp = toOnlineAccountTimestamp(now) + getOnlineTimestampModulus();
-        if (isMemoryPoWActive(now)) {
-            boolean success = computeOurAccountsForTimestamp(nextOnlineAccountsTimestamp);
-            if (!success) {
-                // We didn't compute the required nonce value(s), and so can't proceed until they have been retried
-                return;
-            }
+        boolean success = computeOurAccountsForTimestamp(nextOnlineAccountsTimestamp);
+        if (!success) {
+            // We didn't compute the required nonce value(s), and so can't proceed until they have been retried
+            return;
         }
 
         // 'current' timestamp
@@ -553,21 +574,15 @@ public class OnlineAccountsManager {
 
             // Compute nonce
             Integer nonce;
-            if (isMemoryPoWActive(NTP.getTime())) {
-                try {
-                    nonce = this.computeMemoryPoW(mempowBytes, publicKey, onlineAccountsTimestamp);
-                    if (nonce == null) {
-                        // A nonce is required
-                        return false;
-                    }
-                } catch (TimeoutException e) {
-                    LOGGER.info(String.format("Timed out computing nonce for account %.8s", Base58.encode(publicKey)));
+            try {
+                nonce = this.computeMemoryPoW(mempowBytes, publicKey, onlineAccountsTimestamp);
+                if (nonce == null) {
+                    // A nonce is required
                     return false;
                 }
-            }
-            else {
-                // Send -1 if we haven't computed a nonce due to feature trigger timestamp
-                nonce = -1;
+            } catch (TimeoutException e) {
+                LOGGER.info(String.format("Timed out computing nonce for account %.8s", Base58.encode(publicKey)));
+                return false;
             }
 
             byte[] signature = Qortal25519Extras.signForAggregation(privateKey, timestampBytes);
@@ -576,7 +591,7 @@ public class OnlineAccountsManager {
             OnlineAccountData ourOnlineAccountData = new OnlineAccountData(onlineAccountsTimestamp, signature, publicKey, nonce);
 
             // Make sure to verify before adding
-            if (verifyMemoryPoW(ourOnlineAccountData, NTP.getTime())) {
+            if (verifyMemoryPoW(ourOnlineAccountData, null)) {
                 ourOnlineAccounts.add(ourOnlineAccountData);
             }
         }
@@ -599,12 +614,6 @@ public class OnlineAccountsManager {
 
     // MemoryPoW
 
-    private boolean isMemoryPoWActive(Long timestamp) {
-        if (timestamp >= BlockChain.getInstance().getOnlineAccountsMemoryPoWTimestamp() || Settings.getInstance().isOnlineAccountsMemPoWEnabled()) {
-            return true;
-        }
-        return false;
-    }
     private byte[] getMemoryPoWBytes(byte[] publicKey, long onlineAccountsTimestamp) throws IOException {
         byte[] timestampBytes = Longs.toByteArray(onlineAccountsTimestamp);
 
@@ -616,11 +625,6 @@ public class OnlineAccountsManager {
     }
 
     private Integer computeMemoryPoW(byte[] bytes, byte[] publicKey, long onlineAccountsTimestamp) throws TimeoutException {
-        if (!isMemoryPoWActive(NTP.getTime())) {
-            LOGGER.info("Mempow start timestamp not yet reached, and onlineAccountsMemPoWEnabled not enabled in settings");
-            return null;
-        }
-
         LOGGER.info(String.format("Computing nonce for account %.8s and timestamp %d...", Base58.encode(publicKey), onlineAccountsTimestamp));
 
         // Calculate the time until the next online timestamp and use it as a timeout when computing the nonce
@@ -628,7 +632,8 @@ public class OnlineAccountsManager {
         final long nextOnlineAccountsTimestamp = toOnlineAccountTimestamp(startTime) + getOnlineTimestampModulus();
         long timeUntilNextTimestamp = nextOnlineAccountsTimestamp - startTime;
 
-        Integer nonce = MemoryPoW.compute2(bytes, POW_BUFFER_SIZE, POW_DIFFICULTY, timeUntilNextTimestamp);
+        int difficulty = getPoWDifficulty(onlineAccountsTimestamp);
+        Integer nonce = MemoryPoW.compute2(bytes, getPoWBufferSize(), difficulty, timeUntilNextTimestamp);
 
         double totalSeconds = (NTP.getTime() - startTime) / 1000.0f;
         int minutes = (int) ((totalSeconds % 3600) / 60);
@@ -637,16 +642,15 @@ public class OnlineAccountsManager {
 
         LOGGER.info(String.format("Computed nonce for timestamp %d and account %.8s: %d. Buffer size: %d. Difficulty: %d. " +
                         "Time taken: %02d:%02d. Hashrate: %f", onlineAccountsTimestamp, Base58.encode(publicKey),
-                nonce, POW_BUFFER_SIZE, POW_DIFFICULTY, minutes, seconds, hashRate));
+                nonce, getPoWBufferSize(), difficulty, minutes, seconds, hashRate));
 
         return nonce;
     }
 
-    public boolean verifyMemoryPoW(OnlineAccountData onlineAccountData, Long timestamp) {
-        long memoryPoWStartTimestamp = BlockChain.getInstance().getOnlineAccountsMemoryPoWTimestamp();
-        if (timestamp < memoryPoWStartTimestamp && onlineAccountData.getTimestamp() < memoryPoWStartTimestamp) {
-            // Not active yet, so treat it as valid
-            return true;
+    public boolean verifyMemoryPoW(OnlineAccountData onlineAccountData, long[] workBuffer) {
+        // Require a valid nonce value
+        if (onlineAccountData.getNonce() == null || onlineAccountData.getNonce() < 0) {
+            return false;
         }
 
         int nonce = onlineAccountData.getNonce();
@@ -659,7 +663,7 @@ public class OnlineAccountsManager {
         }
 
         // Verify the nonce
-        return MemoryPoW.verify2(mempowBytes, POW_BUFFER_SIZE, POW_DIFFICULTY, nonce);
+        return MemoryPoW.verify2(mempowBytes, workBuffer, getPoWBufferSize(), getPoWDifficulty(onlineAccountData.getTimestamp()), nonce);
     }
 
 
@@ -697,7 +701,7 @@ public class OnlineAccountsManager {
      */
     // Block::mint() - only wants online accounts with (online) timestamp that matches block's (online) timestamp so they can be added to new block
     public List<OnlineAccountData> getOnlineAccounts(long onlineTimestamp) {
-        LOGGER.info(String.format("caller's timestamp: %d, our timestamps: %s", onlineTimestamp, String.join(", ", this.currentOnlineAccounts.keySet().stream().map(l -> Long.toString(l)).collect(Collectors.joining(", ")))));
+        LOGGER.debug(String.format("caller's timestamp: %d, our timestamps: %s", onlineTimestamp, String.join(", ", this.currentOnlineAccounts.keySet().stream().map(l -> Long.toString(l)).collect(Collectors.joining(", ")))));
 
         return new ArrayList<>(Set.copyOf(this.currentOnlineAccounts.getOrDefault(onlineTimestamp, Collections.emptySet())));
     }
@@ -743,11 +747,12 @@ public class OnlineAccountsManager {
      * Typically called by {@link Block#areOnlineAccountsValid()}
      */
     public void addBlocksOnlineAccounts(Set<OnlineAccountData> blocksOnlineAccounts, Long timestamp) {
-        // We want to add to 'current' in preference if possible
-        if (this.currentOnlineAccounts.containsKey(timestamp)) {
-            addAccounts(blocksOnlineAccounts);
+        // If these are current accounts, then there is no need to cache them, and should instead rely
+        // on the more complete entries we already have in self.currentOnlineAccounts.
+        // Note: since sig-agg, we no longer have individual signatures included in blocks, so we
+        // mustn't add anything to currentOnlineAccounts from here.
+        if (this.currentOnlineAccounts.containsKey(timestamp))
             return;
-        }
 
         // Add to block cache instead
         this.latestBlocksOnlineAccounts.computeIfAbsent(timestamp, k -> ConcurrentHashMap.newKeySet())

src/main/java/org/qortal/controller/Synchronizer.java

@@ -53,7 +53,8 @@ public class Synchronizer extends Thread {
 	/** Maximum number of block signatures we ask from peer in one go */
 	private static final int MAXIMUM_REQUEST_SIZE = 200; // XXX move to Settings?
 
-	private static final long RECOVERY_MODE_TIMEOUT = 10 * 60 * 1000L; // ms
+	/** Maximum number of consecutive failed sync attempts before marking peer as misbehaved */
+	private static final int MAX_CONSECUTIVE_FAILED_SYNC_ATTEMPTS = 3;
 
 
 	private boolean running;
@@ -75,6 +76,8 @@ public class Synchronizer extends Thread {
 	private volatile boolean isSynchronizing = false;
 	/** Temporary estimate of synchronization progress for SysTray use. */
 	private volatile int syncPercent = 0;
+	/** Temporary estimate of blocks remaining for SysTray use. */
+	private volatile int blocksRemaining = 0;
 
 	private static volatile boolean requestSync = false;
 	private boolean syncRequestPending = false;
@@ -180,6 +183,18 @@ public class Synchronizer extends Thread {
 		}
 	}
 
+	public Integer getBlocksRemaining() {
+		synchronized (this.syncLock) {
+			// Report as 0 blocks remaining if the latest block is within the last 60 mins
+			final Long minLatestBlockTimestamp = NTP.getTime() - (60 * 60 * 1000L);
+			if (Controller.getInstance().isUpToDate(minLatestBlockTimestamp)) {
+				return 0;
+			}
+
+			return this.isSynchronizing ? this.blocksRemaining : null;
+		}
+	}
+
 	public void requestSync() {
 		requestSync = true;
 	}
@@ -232,6 +247,9 @@ public class Synchronizer extends Thread {
 		// Disregard peers that are on the same block as last sync attempt and we didn't like their chain
 		peers.removeIf(Controller.hasInferiorChainTip);
 
+		// Disregard peers that have a block with an invalid signer
+		peers.removeIf(Controller.hasInvalidSigner);
+
 		final int peersBeforeComparison = peers.size();
 
 		// Request recent block summaries from the remaining peers, and locate our common block with each
@@ -396,9 +414,10 @@ public class Synchronizer extends Thread {
 					timePeersLastAvailable = NTP.getTime();
 
 				// If enough time has passed, enter recovery mode, which lifts some restrictions on who we can sync with and when we can mint
-				if (NTP.getTime() - timePeersLastAvailable > RECOVERY_MODE_TIMEOUT) {
+				long recoveryModeTimeout = Settings.getInstance().getRecoveryModeTimeout();
+				if (NTP.getTime() - timePeersLastAvailable > recoveryModeTimeout) {
 					if (recoveryMode == false) {
-						LOGGER.info(String.format("Peers have been unavailable for %d minutes. Entering recovery mode...", RECOVERY_MODE_TIMEOUT/60/1000));
+						LOGGER.info(String.format("Peers have been unavailable for %d minutes. Entering recovery mode...", recoveryModeTimeout/60/1000));
 						recoveryMode = true;
 					}
 				}
@@ -1455,6 +1474,12 @@ public class Synchronizer extends Thread {
 
 			repository.saveChanges();
 
+			synchronized (this.syncLock) {
+				if (peer.getChainTipData() != null) {
+					this.blocksRemaining = peer.getChainTipData().getHeight() - newBlock.getBlockData().getHeight();
+				}
+			}
+
 			Controller.getInstance().onNewBlock(newBlock.getBlockData());
 		}
 
@@ -1550,6 +1575,12 @@ public class Synchronizer extends Thread {
 
 			repository.saveChanges();
 
+			synchronized (this.syncLock) {
+				if (peer.getChainTipData() != null) {
+					this.blocksRemaining = peer.getChainTipData().getHeight() - newBlock.getBlockData().getHeight();
+				}
+			}
+
 			Controller.getInstance().onNewBlock(newBlock.getBlockData());
 		}
 
@@ -1591,8 +1622,20 @@ public class Synchronizer extends Thread {
 		Message getBlockMessage = new GetBlockMessage(signature);
 
 		Message message = peer.getResponse(getBlockMessage);
-		if (message == null)
+		if (message == null) {
+			peer.getPeerData().incrementFailedSyncCount();
+			if (peer.getPeerData().getFailedSyncCount() >= MAX_CONSECUTIVE_FAILED_SYNC_ATTEMPTS) {
+				// Several failed attempts, so mark peer as misbehaved
+				LOGGER.info("Marking peer {} as misbehaved due to {} failed sync attempts", peer, peer.getPeerData().getFailedSyncCount());
+				Network.getInstance().peerMisbehaved(peer);
+			}
 			return null;
+		}
+
+		// Reset failed sync count now that we have a block response
+		// FUTURE: we could move this to the end of the sync process, but to reduce risk this can be done
+		// at a later stage. For now we are only defending against serialization errors or no responses.
+		peer.getPeerData().setFailedSyncCount(0);
 
 		switch (message.getType()) {
 			case BLOCK: {

src/main/java/org/qortal/controller/tradebot/LitecoinACCTv3TradeBot.java

@@ -19,6 +19,7 @@ import org.qortal.data.transaction.MessageTransactionData;
 import org.qortal.group.Group;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
 import org.qortal.transaction.DeployAtTransaction;
 import org.qortal.transaction.MessageTransaction;
 import org.qortal.transaction.Transaction.ValidationResult;
@@ -317,20 +318,27 @@ public class LitecoinACCTv3TradeBot implements AcctTradeBot {
 
 		boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, messageData);
 		if (!isMessageAlreadySent) {
-			PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
-			MessageTransaction messageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, messageData, false, false);
+			// Do this in a new thread so caller doesn't have to wait for computeNonce()
+			// In the unlikely event that the transaction doesn't validate then the buy won't happen and eventually Alice's AT will be refunded
+			new Thread(() -> {
+				try (final Repository threadsRepository = RepositoryManager.getRepository()) {
+					PrivateKeyAccount sender = new PrivateKeyAccount(threadsRepository, tradeBotData.getTradePrivateKey());
+					MessageTransaction messageTransaction = MessageTransaction.build(threadsRepository, sender, Group.NO_GROUP, messageRecipient, messageData, false, false);
 
-			messageTransaction.computeNonce();
-			messageTransaction.sign(sender);
+					messageTransaction.computeNonce();
+					messageTransaction.sign(sender);
 
-			// reset repository state to prevent deadlock
-			repository.discardChanges();
-			ValidationResult result = messageTransaction.importAsUnconfirmed();
+					// reset repository state to prevent deadlock
+					threadsRepository.discardChanges();
+					ValidationResult result = messageTransaction.importAsUnconfirmed();
 
-			if (result != ValidationResult.OK) {
-				LOGGER.warn(() -> String.format("Unable to send MESSAGE to Bob's trade-bot %s: %s", messageRecipient, result.name()));
-				return ResponseResult.NETWORK_ISSUE;
-			}
+					if (result != ValidationResult.OK) {
+						LOGGER.warn(() -> String.format("Unable to send MESSAGE to Bob's trade-bot %s: %s", messageRecipient, result.name()));
+					}
+				} catch (DataException e) {
+					LOGGER.warn(() -> String.format("Unable to send MESSAGE to Bob's trade-bot %s: %s", messageRecipient, e.getMessage()));
+				}
+			}, "TradeBot response").start();
 		}
 
 		TradeBot.updateTradeBotState(repository, tradeBotData, () -> String.format("Funding P2SH-A %s. Messaged Bob. Waiting for AT-lock", p2shAddress));

src/main/java/org/qortal/crypto/MemoryPoW.java

@@ -99,6 +99,10 @@ public class MemoryPoW {
 	}
 
 	public static boolean verify2(byte[] data, int workBufferLength, long difficulty, int nonce) {
+		return verify2(data, null, workBufferLength, difficulty, nonce);
+	}
+
+	public static boolean verify2(byte[] data, long[] workBuffer, int workBufferLength, long difficulty, int nonce) {
 		// Hash data with SHA256
 		byte[] hash = Crypto.digest(data);
 
@@ -111,7 +115,10 @@ public class MemoryPoW {
 		byteBuffer = null;
 
 		int longBufferLength = workBufferLength / 8;
-		long[] workBuffer = new long[longBufferLength];
+
+		if (workBuffer == null)
+			workBuffer = new long[longBufferLength];
+
 		long[] state = new long[4];
 
 		long seed = 8682522807148012L;

src/main/java/org/qortal/data/account/AccountData.java

@@ -18,6 +18,7 @@ public class AccountData {
 	protected int level;
 	protected int blocksMinted;
 	protected int blocksMintedAdjustment;
+	protected int blocksMintedPenalty;
 
 	// Constructors
 
@@ -25,7 +26,7 @@ public class AccountData {
 	protected AccountData() {
 	}
 
-	public AccountData(String address, byte[] reference, byte[] publicKey, int defaultGroupId, int flags, int level, int blocksMinted, int blocksMintedAdjustment) {
+	public AccountData(String address, byte[] reference, byte[] publicKey, int defaultGroupId, int flags, int level, int blocksMinted, int blocksMintedAdjustment, int blocksMintedPenalty) {
 		this.address = address;
 		this.reference = reference;
 		this.publicKey = publicKey;
@@ -34,10 +35,11 @@ public class AccountData {
 		this.level = level;
 		this.blocksMinted = blocksMinted;
 		this.blocksMintedAdjustment = blocksMintedAdjustment;
+		this.blocksMintedPenalty = blocksMintedPenalty;
 	}
 
 	public AccountData(String address) {
-		this(address, null, null, Group.NO_GROUP, 0, 0, 0, 0);
+		this(address, null, null, Group.NO_GROUP, 0, 0, 0, 0, 0);
 	}
 
 	// Getters/Setters
@@ -102,6 +104,14 @@ public class AccountData {
 		this.blocksMintedAdjustment = blocksMintedAdjustment;
 	}
 
+	public int getBlocksMintedPenalty() {
+		return this.blocksMintedPenalty;
+	}
+
+	public void setBlocksMintedPenalty(int blocksMintedPenalty) {
+		this.blocksMintedPenalty = blocksMintedPenalty;
+	}
+
 	// Comparison
 
 	@Override

src/main/java/org/qortal/data/account/AccountPenaltyData.java

@@ -0,0 +1,52 @@
+package org.qortal.data.account;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+
+// All properties to be converted to JSON via JAXB
+@XmlAccessorType(XmlAccessType.FIELD)
+public class AccountPenaltyData {
+
+	// Properties
+	private String address;
+	private int blocksMintedPenalty;
+
+	// Constructors
+
+	// necessary for JAXB
+	protected AccountPenaltyData() {
+	}
+
+	public AccountPenaltyData(String address, int blocksMintedPenalty) {
+		this.address = address;
+		this.blocksMintedPenalty = blocksMintedPenalty;
+	}
+
+	// Getters/Setters
+
+	public String getAddress() {
+		return this.address;
+	}
+
+	public int getBlocksMintedPenalty() {
+		return this.blocksMintedPenalty;
+	}
+
+	public String toString() {
+		return String.format("%s has penalty %d", this.address, this.blocksMintedPenalty);
+	}
+
+	@Override
+	public boolean equals(Object b) {
+		if (!(b instanceof AccountPenaltyData))
+			return false;
+
+		return this.getAddress().equals(((AccountPenaltyData) b).getAddress());
+	}
+
+	@Override
+	public int hashCode() {
+		return address.hashCode();
+	}
+
+}

src/main/java/org/qortal/data/network/PeerData.java

@@ -28,6 +28,9 @@ public class PeerData {
 	private Long addedWhen;
 	private String addedBy;
 
+	/** The number of consecutive times we failed to sync with this peer */
+	private int failedSyncCount = 0;
+
 	// Constructors
 
 	// necessary for JAXB serialization
@@ -92,6 +95,18 @@ public class PeerData {
 		return this.addedBy;
 	}
 
+	public int getFailedSyncCount() {
+		return this.failedSyncCount;
+	}
+
+	public void setFailedSyncCount(int failedSyncCount) {
+		this.failedSyncCount = failedSyncCount;
+	}
+
+	public void incrementFailedSyncCount() {
+		this.failedSyncCount++;
+	}
+
 	// Pretty peerAddress getter for JAXB
 	@XmlElement(name = "address")
 	protected String getPrettyAddress() {

src/main/java/org/qortal/data/transaction/TransactionData.java

@@ -128,6 +128,10 @@ public abstract class TransactionData {
 		return this.txGroupId;
 	}
 
+	public void setTxGroupId(int txGroupId) {
+		this.txGroupId = txGroupId;
+	}
+
 	public byte[] getReference() {
 		return this.reference;
 	}

src/main/java/org/qortal/group/Group.java

@@ -80,6 +80,9 @@ public class Group {
 	// Useful constants
 	public static final int NO_GROUP = 0;
 
+	// Null owner address corresponds with public key "11111111111111111111111111111111"
+	public static String NULL_OWNER_ADDRESS = "QdSnUy6sUiEnaN87dWmE92g1uQjrvPgrWG";
+
 	public static final int MIN_NAME_SIZE = 3;
 	public static final int MAX_NAME_SIZE = 32;
 	public static final int MAX_DESCRIPTION_SIZE = 128;

src/main/java/org/qortal/network/Handshake.java

@@ -265,7 +265,7 @@ public enum Handshake {
 	private static final long PEER_VERSION_131 = 0x0100030001L;
 
 	/** Minimum peer version that we are allowed to communicate with */
-	private static final String MIN_PEER_VERSION = "3.1.0";
+	private static final String MIN_PEER_VERSION = "3.7.0";
 
 	private static final int POW_BUFFER_SIZE_PRE_131 = 8 * 1024 * 1024; // bytes
 	private static final int POW_DIFFICULTY_PRE_131 = 8; // leading zero bits

src/main/java/org/qortal/network/message/AccountMessage.java

@@ -41,6 +41,8 @@ public class AccountMessage extends Message {
 
 			bytes.write(Ints.toByteArray(accountData.getBlocksMintedAdjustment()));
 
+			bytes.write(Ints.toByteArray(accountData.getBlocksMintedPenalty()));
+
 		} catch (IOException e) {
 			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
 		}
@@ -80,7 +82,9 @@ public class AccountMessage extends Message {
 
 		int blocksMintedAdjustment = byteBuffer.getInt();
 
-		AccountData accountData = new AccountData(address, reference, publicKey, defaultGroupId, flags, level, blocksMinted, blocksMintedAdjustment);
+		int blocksMintedPenalty = byteBuffer.getInt();
+
+		AccountData accountData = new AccountData(address, reference, publicKey, defaultGroupId, flags, level, blocksMinted, blocksMintedAdjustment, blocksMintedPenalty);
 		return new AccountMessage(id, accountData);
 	}
 

src/main/java/org/qortal/repository/AccountRepository.java

@@ -1,13 +1,9 @@
 package org.qortal.repository;
 
 import java.util.List;
+import java.util.Set;
 
-import org.qortal.data.account.AccountBalanceData;
-import org.qortal.data.account.AccountData;
-import org.qortal.data.account.EligibleQoraHolderData;
-import org.qortal.data.account.MintingAccountData;
-import org.qortal.data.account.QortFromQoraData;
-import org.qortal.data.account.RewardShareData;
+import org.qortal.data.account.*;
 
 public interface AccountRepository {
 
@@ -19,6 +15,9 @@ public interface AccountRepository {
 	/** Returns accounts with <b>any</b> bit set in given mask. */
 	public List<AccountData> getFlaggedAccounts(int mask) throws DataException;
 
+	/** Returns accounts with a blockedMintedPenalty */
+	public List<AccountData> getPenaltyAccounts() throws DataException;
+
 	/** Returns account's last reference or null if not set or account not found. */
 	public byte[] getLastReference(String address) throws DataException;
 
@@ -100,6 +99,18 @@ public interface AccountRepository {
 	 */
 	public void modifyMintedBlockCounts(List<String> addresses, int delta) throws DataException;
 
+	/** Returns account's block minted penalty count or null if account not found. */
+	public Integer getBlocksMintedPenaltyCount(String address) throws DataException;
+
+	/**
+	 * Sets blocks minted penalties for given list of accounts.
+	 * This replaces the existing values rather than modifying them by a delta.
+	 *
+	 * @param accountPenalties
+	 * @throws DataException
+	 */
+	public void updateBlocksMintedPenalties(Set<AccountPenaltyData> accountPenalties) throws DataException;
+
 	/** Delete account from repository. */
 	public void delete(String address) throws DataException;
 

src/main/java/org/qortal/repository/TransactionRepository.java

@@ -179,6 +179,15 @@ public interface TransactionRepository {
 	public List<TransferAssetTransactionData> getAssetTransfers(long assetId, String address, Integer limit, Integer offset, Boolean reverse)
 			throws DataException;
 
+	/**
+	 * Returns list of reward share transaction creators, excluding self shares.
+	 * This uses confirmed transactions only.
+	 *
+	 * @return
+	 * @throws DataException
+	 */
+	public List<String> getConfirmedRewardShareCreatorsExcludingSelfShares() throws DataException;
+
 	/**
 	 * Returns list of transactions pending approval, with optional txGgroupId filtering.
 	 * <p>

src/main/java/org/qortal/repository/hsqldb/HSQLDBAccountRepository.java

@@ -6,15 +6,11 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
 import java.util.stream.Collectors;
 
 import org.qortal.asset.Asset;
-import org.qortal.data.account.AccountBalanceData;
-import org.qortal.data.account.AccountData;
-import org.qortal.data.account.EligibleQoraHolderData;
-import org.qortal.data.account.MintingAccountData;
-import org.qortal.data.account.QortFromQoraData;
-import org.qortal.data.account.RewardShareData;
+import org.qortal.data.account.*;
 import org.qortal.repository.AccountRepository;
 import org.qortal.repository.DataException;
 
@@ -30,7 +26,7 @@ public class HSQLDBAccountRepository implements AccountRepository {
 
 	@Override
 	public AccountData getAccount(String address) throws DataException {
-		String sql = "SELECT reference, public_key, default_group_id, flags, level, blocks_minted, blocks_minted_adjustment FROM Accounts WHERE account = ?";
+		String sql = "SELECT reference, public_key, default_group_id, flags, level, blocks_minted, blocks_minted_adjustment, blocks_minted_penalty FROM Accounts WHERE account = ?";
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql, address)) {
 			if (resultSet == null)
@@ -43,8 +39,9 @@ public class HSQLDBAccountRepository implements AccountRepository {
 			int level = resultSet.getInt(5);
 			int blocksMinted = resultSet.getInt(6);
 			int blocksMintedAdjustment = resultSet.getInt(7);
+			int blocksMintedPenalty = resultSet.getInt(8);
 
-			return new AccountData(address, reference, publicKey, defaultGroupId, flags, level, blocksMinted, blocksMintedAdjustment);
+			return new AccountData(address, reference, publicKey, defaultGroupId, flags, level, blocksMinted, blocksMintedAdjustment, blocksMintedPenalty);
 		} catch (SQLException e) {
 			throw new DataException("Unable to fetch account info from repository", e);
 		}
@@ -52,7 +49,7 @@ public class HSQLDBAccountRepository implements AccountRepository {
 
 	@Override
 	public List<AccountData> getFlaggedAccounts(int mask) throws DataException {
-		String sql = "SELECT reference, public_key, default_group_id, flags, level, blocks_minted, blocks_minted_adjustment, account FROM Accounts WHERE BITAND(flags, ?) != 0";
+		String sql = "SELECT reference, public_key, default_group_id, flags, level, blocks_minted, blocks_minted_adjustment, blocks_minted_penalty, account FROM Accounts WHERE BITAND(flags, ?) != 0";
 
 		List<AccountData> accounts = new ArrayList<>();
 
@@ -68,9 +65,10 @@ public class HSQLDBAccountRepository implements AccountRepository {
 				int level = resultSet.getInt(5);
 				int blocksMinted = resultSet.getInt(6);
 				int blocksMintedAdjustment = resultSet.getInt(7);
-				String address = resultSet.getString(8);
+				int blocksMintedPenalty = resultSet.getInt(8);
+				String address = resultSet.getString(9);
 
-				accounts.add(new AccountData(address, reference, publicKey, defaultGroupId, flags, level, blocksMinted, blocksMintedAdjustment));
+				accounts.add(new AccountData(address, reference, publicKey, defaultGroupId, flags, level, blocksMinted, blocksMintedAdjustment, blocksMintedPenalty));
 			} while (resultSet.next());
 
 			return accounts;
@@ -79,6 +77,36 @@ public class HSQLDBAccountRepository implements AccountRepository {
 		}
 	}
 
+	@Override
+	public List<AccountData> getPenaltyAccounts() throws DataException {
+		String sql = "SELECT reference, public_key, default_group_id, flags, level, blocks_minted, blocks_minted_adjustment, blocks_minted_penalty, account FROM Accounts WHERE blocks_minted_penalty != 0";
+
+		List<AccountData> accounts = new ArrayList<>();
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql)) {
+			if (resultSet == null)
+				return accounts;
+
+			do {
+				byte[] reference = resultSet.getBytes(1);
+				byte[] publicKey = resultSet.getBytes(2);
+				int defaultGroupId = resultSet.getInt(3);
+				int flags = resultSet.getInt(4);
+				int level = resultSet.getInt(5);
+				int blocksMinted = resultSet.getInt(6);
+				int blocksMintedAdjustment = resultSet.getInt(7);
+				int blocksMintedPenalty = resultSet.getInt(8);
+				String address = resultSet.getString(9);
+
+				accounts.add(new AccountData(address, reference, publicKey, defaultGroupId, flags, level, blocksMinted, blocksMintedAdjustment, blocksMintedPenalty));
+			} while (resultSet.next());
+
+			return accounts;
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch penalty accounts from repository", e);
+		}
+	}
+
 	@Override
 	public byte[] getLastReference(String address) throws DataException {
 		String sql = "SELECT reference FROM Accounts WHERE account = ?";
@@ -298,6 +326,39 @@ public class HSQLDBAccountRepository implements AccountRepository {
 		}
 	}
 
+	@Override
+	public Integer getBlocksMintedPenaltyCount(String address) throws DataException {
+		String sql = "SELECT blocks_minted_penalty FROM Accounts WHERE account = ?";
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql, address)) {
+			if (resultSet == null)
+				return null;
+
+			return resultSet.getInt(1);
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch account's block minted penalty count from repository", e);
+		}
+	}
+	public void updateBlocksMintedPenalties(Set<AccountPenaltyData> accountPenalties) throws DataException {
+		// Nothing to do?
+		if (accountPenalties == null || accountPenalties.isEmpty())
+			return;
+
+		// Map balance changes into SQL bind params, filtering out no-op changes
+		List<Object[]> updateBlocksMintedPenaltyParams = accountPenalties.stream()
+				.map(accountPenalty -> new Object[] { accountPenalty.getAddress(), accountPenalty.getBlocksMintedPenalty(), accountPenalty.getBlocksMintedPenalty() })
+				.collect(Collectors.toList());
+
+		// Perform actual balance changes
+		String sql = "INSERT INTO Accounts (account, blocks_minted_penalty) VALUES (?, ?) " +
+				"ON DUPLICATE KEY UPDATE blocks_minted_penalty = blocks_minted_penalty + ?";
+		try {
+			this.repository.executeCheckedBatchUpdate(sql, updateBlocksMintedPenaltyParams);
+		} catch (SQLException e) {
+			throw new DataException("Unable to set blocks minted penalties in repository", e);
+		}
+	}
+
 	@Override
 	public void delete(String address) throws DataException {
 		// NOTE: Account balances are deleted automatically by the database thanks to "ON DELETE CASCADE" in AccountBalances' FOREIGN KEY

src/main/java/org/qortal/repository/hsqldb/HSQLDBDatabaseUpdates.java

@@ -975,6 +975,11 @@ public class HSQLDBDatabaseUpdates {
 					stmt.execute("ALTER TABLE TradeBotStates ALTER COLUMN receiving_account_info SET DATA TYPE VARBINARY(128)");
 					break;
 
+				case 44:
+					// Add blocks minted penalty
+					stmt.execute("ALTER TABLE Accounts ADD blocks_minted_penalty INTEGER NOT NULL DEFAULT 0");
+					break;
+
 				default:
 					// nothing to do
 					return false;

src/main/java/org/qortal/repository/hsqldb/transaction/HSQLDBTransactionRepository.java

@@ -7,11 +7,7 @@ import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.sql.ResultSet;
 import java.sql.SQLException;
-import java.util.ArrayList;
-import java.util.EnumMap;
-import java.util.EnumSet;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -969,6 +965,33 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 		}
 	}
 
+	public List<String> getConfirmedRewardShareCreatorsExcludingSelfShares() throws DataException {
+		List<String> rewardShareCreators = new ArrayList<>();
+
+		String sql = "SELECT account "
+				+ "FROM RewardShareTransactions "
+				+ "JOIN Accounts ON Accounts.public_key = RewardShareTransactions.minter_public_key "
+				+ "JOIN Transactions ON Transactions.signature = RewardShareTransactions.signature "
+				+ "WHERE block_height IS NOT NULL AND RewardShareTransactions.recipient != Accounts.account "
+				+ "GROUP BY account "
+				+ "ORDER BY account";
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql)) {
+			if (resultSet == null)
+				return rewardShareCreators;
+
+			do {
+				String address = resultSet.getString(1);
+
+				rewardShareCreators.add(address);
+			} while (resultSet.next());
+
+			return rewardShareCreators;
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch reward share creators from repository", e);
+		}
+	}
+
 	@Override
 	public List<TransactionData> getApprovalPendingTransactions(Integer txGroupId, Integer limit, Integer offset, Boolean reverse) throws DataException {
 		StringBuilder sql = new StringBuilder(512);

src/main/java/org/qortal/settings/Settings.java

@@ -184,6 +184,8 @@ public class Settings {
 
 	// Peer-to-peer related
 	private boolean isTestNet = false;
+	/** Single node testnet mode */
+	private boolean singleNodeTestnet = false;
 	/** Port number for inbound peer-to-peer connections. */
 	private Integer listenPort;
 	/** Whether to attempt to open the listen port via UPnP */
@@ -203,8 +205,11 @@ public class Settings {
 	/** Maximum number of retry attempts if a peer fails to respond with the requested data */
 	private int maxRetries = 2;
 
+	/** The number of seconds of no activity before recovery mode begins */
+	public long recoveryModeTimeout = 10 * 60 * 1000L;
+
 	/** Minimum peer version number required in order to sync with them */
-	private String minPeerVersion = "3.3.7";
+	private String minPeerVersion = "3.7.0";
 	/** Whether to allow connections with peers below minPeerVersion
 	 * If true, we won't sync with them but they can still sync with us, and will show in the peers list
 	 * If false, sync will be blocked both ways, and they will not appear in the peers list */
@@ -290,10 +295,6 @@ public class Settings {
 	/** Additional offset added to values returned by NTP.getTime() */
 	private Long testNtpOffset = null;
 
-	// Online accounts
-
-	/** Whether to opt-in to mempow computations for online accounts, ahead of general release */
-	private boolean onlineAccountsMemPoWEnabled = false;
 
 
 	/* Foreign chains */
@@ -490,7 +491,7 @@ public class Settings {
 
 	private void validate() {
 		// Validation goes here
-		if (this.minBlockchainPeers < 1)
+		if (this.minBlockchainPeers < 1 && !singleNodeTestnet)
 			throwValidationError("minBlockchainPeers must be at least 1");
 
 		if (this.apiKey != null && this.apiKey.trim().length() < 8)
@@ -647,6 +648,10 @@ public class Settings {
 		return this.isTestNet;
 	}
 
+	public boolean isSingleNodeTestnet() {
+		return this.singleNodeTestnet;
+	}
+
 	public int getListenPort() {
 		if (this.listenPort != null)
 			return this.listenPort;
@@ -667,6 +672,9 @@ public class Settings {
 	}
 
 	public int getMinBlockchainPeers() {
+		if (singleNodeTestnet)
+			return 0;
+
 		return this.minBlockchainPeers;
 	}
 
@@ -692,6 +700,10 @@ public class Settings {
 
 	public int getMaxRetries() { return this.maxRetries; }
 
+	public long getRecoveryModeTimeout() {
+		return recoveryModeTimeout;
+	}
+
 	public String getMinPeerVersion() { return this.minPeerVersion; }
 
 	public boolean getAllowConnectionsWithOlderPeerVersions() { return this.allowConnectionsWithOlderPeerVersions; }
@@ -800,10 +812,6 @@ public class Settings {
 		return this.testNtpOffset;
 	}
 
-	public boolean isOnlineAccountsMemPoWEnabled() {
-		return this.onlineAccountsMemPoWEnabled;
-	}
-
 	public long getRepositoryBackupInterval() {
 		return this.repositoryBackupInterval;
 	}

src/main/java/org/qortal/transaction/AddGroupAdminTransaction.java

@@ -2,6 +2,7 @@ package org.qortal.transaction;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 
 import org.qortal.account.Account;
 import org.qortal.asset.Asset;
@@ -64,15 +65,24 @@ public class AddGroupAdminTransaction extends Transaction {
 
 		Account owner = getOwner();
 		String groupOwner = this.repository.getGroupRepository().getOwner(groupId);
+		boolean groupOwnedByNullAccount = Objects.equals(groupOwner, Group.NULL_OWNER_ADDRESS);
 
-		// Check transaction's public key matches group's current owner
-		if (!owner.getAddress().equals(groupOwner))
+		// Require approval if transaction relates to a group owned by the null account
+		if (groupOwnedByNullAccount && !this.needsGroupApproval())
+			return ValidationResult.GROUP_APPROVAL_REQUIRED;
+
+		// Check transaction's public key matches group's current owner (except for groups owned by the null account)
+		if (!groupOwnedByNullAccount && !owner.getAddress().equals(groupOwner))
 			return ValidationResult.INVALID_GROUP_OWNER;
 
 		// Check address is a group member
 		if (!this.repository.getGroupRepository().memberExists(groupId, memberAddress))
 			return ValidationResult.NOT_GROUP_MEMBER;
 
+		// Check transaction creator is a group member
+		if (!this.repository.getGroupRepository().memberExists(groupId, this.getCreator().getAddress()))
+			return ValidationResult.NOT_GROUP_MEMBER;
+
 		// Check group member is not already an admin
 		if (this.repository.getGroupRepository().adminExists(groupId, memberAddress))
 			return ValidationResult.ALREADY_GROUP_ADMIN;

src/main/java/org/qortal/transaction/RemoveGroupAdminTransaction.java

@@ -2,6 +2,7 @@ package org.qortal.transaction;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 
 import org.qortal.account.Account;
 import org.qortal.asset.Asset;
@@ -65,11 +66,21 @@ public class RemoveGroupAdminTransaction extends Transaction {
 			return ValidationResult.GROUP_DOES_NOT_EXIST;
 
 		Account owner = getOwner();
+		String groupOwner = this.repository.getGroupRepository().getOwner(groupId);
+		boolean groupOwnedByNullAccount = Objects.equals(groupOwner, Group.NULL_OWNER_ADDRESS);
 
-		// Check transaction's public key matches group's current owner
-		if (!owner.getAddress().equals(groupData.getOwner()))
+		// Require approval if transaction relates to a group owned by the null account
+		if (groupOwnedByNullAccount && !this.needsGroupApproval())
+			return ValidationResult.GROUP_APPROVAL_REQUIRED;
+
+		// Check transaction's public key matches group's current owner (except for groups owned by the null account)
+		if (!groupOwnedByNullAccount && !owner.getAddress().equals(groupOwner))
 			return ValidationResult.INVALID_GROUP_OWNER;
 
+		// Check transaction creator is a group member
+		if (!this.repository.getGroupRepository().memberExists(groupId, this.getCreator().getAddress()))
+			return ValidationResult.NOT_GROUP_MEMBER;
+
 		Account admin = getAdmin();
 
 		// Check member is an admin

src/main/java/org/qortal/transaction/Transaction.java

@@ -1,13 +1,7 @@
 package org.qortal.transaction;
 
 import java.math.BigInteger;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Comparator;
-import java.util.EnumSet;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Predicate;
 
@@ -69,8 +63,8 @@ public abstract class Transaction {
 		AT(21, false),
 		CREATE_GROUP(22, true),
 		UPDATE_GROUP(23, true),
-		ADD_GROUP_ADMIN(24, false),
-		REMOVE_GROUP_ADMIN(25, false),
+		ADD_GROUP_ADMIN(24, true),
+		REMOVE_GROUP_ADMIN(25, true),
 		GROUP_BAN(26, false),
 		CANCEL_GROUP_BAN(27, false),
 		GROUP_KICK(28, false),
@@ -250,6 +244,8 @@ public abstract class Transaction {
 		INVALID_TIMESTAMP_SIGNATURE(95),
 		ADDRESS_BLOCKED(96),
 		NAME_BLOCKED(97),
+		GROUP_APPROVAL_REQUIRED(98),
+		ACCOUNT_NOT_TRANSFERABLE(99),
 		INVALID_BUT_OK(999),
 		NOT_YET_RELEASED(1000);
 
@@ -760,9 +756,13 @@ public abstract class Transaction {
 			// Group no longer exists? Possibly due to blockchain orphaning undoing group creation?
 			return true; // stops tx being included in block but it will eventually expire
 
+		String groupOwner = this.repository.getGroupRepository().getOwner(txGroupId);
+		boolean groupOwnedByNullAccount = Objects.equals(groupOwner, Group.NULL_OWNER_ADDRESS);
+
 		// If transaction's creator is group admin (of group with ID txGroupId) then auto-approve
+		// This is disabled for null-owned groups, since these require approval from other admins
 		PublicKeyAccount creator = this.getCreator();
-		if (groupRepository.adminExists(txGroupId, creator.getAddress()))
+		if (!groupOwnedByNullAccount && groupRepository.adminExists(txGroupId, creator.getAddress()))
 			return false;
 
 		return true;

src/main/java/org/qortal/transaction/TransferPrivsTransaction.java

@@ -67,6 +67,11 @@ public class TransferPrivsTransaction extends Transaction {
 		if (getSender().getConfirmedBalance(Asset.QORT) < this.transferPrivsTransactionData.getFee())
 			return ValidationResult.NO_BALANCE;
 
+		// Check sender doesn't have a blocksMintedPenalty, as these accounts cannot be transferred
+		AccountData senderAccountData = this.repository.getAccountRepository().getAccount(getSender().getAddress());
+		if (senderAccountData == null || senderAccountData.getBlocksMintedPenalty() != 0)
+			return ValidationResult.ACCOUNT_NOT_TRANSFERABLE;
+
 		return ValidationResult.OK;
 	}
 

src/main/java/org/qortal/transform/block/BlockTransformer.java

@@ -235,7 +235,7 @@ public class BlockTransformer extends Transformer {
 			// Online accounts timestamp is only present if there are also signatures
 			onlineAccountsTimestamp = byteBuffer.getLong();
 
-			final int signaturesByteLength = getOnlineAccountSignaturesLength(onlineAccountsSignaturesCount, onlineAccountsCount, timestamp);
+			final int signaturesByteLength = (onlineAccountsSignaturesCount * Transformer.SIGNATURE_LENGTH) + (onlineAccountsCount * INT_LENGTH);
 			if (signaturesByteLength > BlockChain.getInstance().getMaxBlockSize())
 				throw new TransformationException("Byte data too long for online accounts signatures");
 
@@ -511,16 +511,6 @@ public class BlockTransformer extends Transformer {
 
 		return nonces;
 	}
-	public static int getOnlineAccountSignaturesLength(int onlineAccountsSignaturesCount, int onlineAccountCount, long blockTimestamp) {
-		if (blockTimestamp >= BlockChain.getInstance().getOnlineAccountsMemoryPoWTimestamp()) {
-			// Once mempow is active, we expect the online account signatures to be appended with the nonce values
-			return (onlineAccountsSignaturesCount * Transformer.SIGNATURE_LENGTH) + (onlineAccountCount * INT_LENGTH);
-		}
-		else {
-			// Before mempow, only the online account signatures were included (which will likely be a single signature)
-			return onlineAccountsSignaturesCount * Transformer.SIGNATURE_LENGTH;
-		}
-	}
 
 	public static byte[] extract(byte[] input, int pos, int length) {
 		byte[] output = new byte[length];

src/main/resources/blockchain.json

@@ -24,7 +24,7 @@
 	"onlineAccountSignaturesMinLifetime": 43200000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
 	"onlineAccountsModulusV2Timestamp": 1659801600000,
-	"onlineAccountsMemoryPoWTimestamp": 9999999999999,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 1670230000000,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 5.00 },
 		{ "height": 259201, "reward": 4.75 },
@@ -80,7 +80,10 @@
 		"calcChainWeightTimestamp": 1620579600000,
 		"transactionV5Timestamp": 1642176000000,
 		"transactionV6Timestamp": 9999999999999,
-		"disableReferenceTimestamp": 1655222400000
+		"disableReferenceTimestamp": 1655222400000,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 1093400,
+		"selfSponsorshipAlgoV1Height": 1092400
 	},
 	"genesisInfo": {
 		"version": 4,

src/main/resources/i18n/SysTray_de.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = Automatisches Update
 
 BLOCK_HEIGHT = height
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = Build-Version
 
 CHECK_TIME_ACCURACY = Prüfe Zeitgenauigkeit

src/main/resources/i18n/SysTray_en.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = Auto Update
 
 BLOCK_HEIGHT = height
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = Build version
 
 CHECK_TIME_ACCURACY = Check time accuracy

src/main/resources/i18n/SysTray_es.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = Actualización automática
 
 BLOCK_HEIGHT = altura
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = Versión de compilación
 
 CHECK_TIME_ACCURACY = Comprobar la precisión del tiempo

src/main/resources/i18n/SysTray_fi.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = Automaattinen päivitys
 
 BLOCK_HEIGHT = korkeus
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = Versio
 
 CHECK_TIME_ACCURACY = Tarkista ajan tarkkuus

src/main/resources/i18n/SysTray_fr.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = Mise à jour automatique
 
 BLOCK_HEIGHT = hauteur
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = Numéro de version
 
 CHECK_TIME_ACCURACY = Vérifier l'heure

src/main/resources/i18n/SysTray_hu.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = Automatikus Frissítés
 
 BLOCK_HEIGHT = blokkmagasság
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = Verzió
 
 CHECK_TIME_ACCURACY = Óra pontosságának ellenőrzése

src/main/resources/i18n/SysTray_it.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = Aggiornamento automatico
 
 BLOCK_HEIGHT = altezza
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = Versione
 
 CHECK_TIME_ACCURACY = Controlla la precisione dell'ora

src/main/resources/i18n/SysTray_ko.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = 자동 업데이트
 
 BLOCK_HEIGHT = 높이
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = 빌드 버전
 
 CHECK_TIME_ACCURACY = 시간 정확도 점검

src/main/resources/i18n/SysTray_nl.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = Automatische Update
 
 BLOCK_HEIGHT = Block hoogte
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = Versie nummer
 
 CHECK_TIME_ACCURACY = Controleer accuraatheid van de tijd

src/main/resources/i18n/SysTray_ro.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = Actualizare automata
 
 BLOCK_HEIGHT = dimensiune
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = versiunea compilatiei
 
 CHECK_TIME_ACCURACY = verificare exactitate ora

src/main/resources/i18n/SysTray_ru.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = Автоматическое обновление
 
 BLOCK_HEIGHT = Высота блока
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = Версия сборки
 
 CHECK_TIME_ACCURACY = Проверка точного времени

src/main/resources/i18n/SysTray_sv.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = Automatisk uppdatering
 
 BLOCK_HEIGHT = höjd
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = Byggversion
 
 CHECK_TIME_ACCURACY = Kontrollera tidens noggrannhet

src/main/resources/i18n/SysTray_zh_CN.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = 自动更新
 
 BLOCK_HEIGHT = 区块高度
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = 版本
 
 CHECK_TIME_ACCURACY = 检查时间准确性

src/main/resources/i18n/SysTray_zh_TW.properties

@@ -7,6 +7,8 @@ AUTO_UPDATE = 自動更新
 
 BLOCK_HEIGHT = 區塊高度
 
+BLOCKS_REMAINING = blocks remaining
+
 BUILD_VERSION = 版本
 
 CHECK_TIME_ACCURACY = 檢查時間準確性

src/test/java/org/qortal/test/arbitrary/ArbitraryServiceTests.java

@@ -102,77 +102,77 @@ public class ArbitraryServiceTests extends Common {
     }
 
     @Test
-    public void testValidQortalMetadata() throws IOException {
-        // Metadata is to describe an arbitrary resource (title, description, tags, etc)
-        String dataString = "{\"title\":\"Test Title\", \"description\":\"Test description\", \"tags\":[\"test\"]}";
+    public void testValidateGifRepository() throws IOException {
+        // Generate some random data
+        byte[] data = new byte[1024];
+        new Random().nextBytes(data);
 
-        // Write to temp path
-        Path path = Files.createTempFile("testValidQortalMetadata", null);
+        // Write the data to several files in a temp path
+        Path path = Files.createTempDirectory("testValidateGifRepository");
         path.toFile().deleteOnExit();
-        Files.write(path, dataString.getBytes(), StandardOpenOption.CREATE);
+        Files.write(Paths.get(path.toString(), "image1.gif"), data, StandardOpenOption.CREATE);
+        Files.write(Paths.get(path.toString(), "image2.gif"), data, StandardOpenOption.CREATE);
+        Files.write(Paths.get(path.toString(), "image3.gif"), data, StandardOpenOption.CREATE);
 
-        Service service = Service.QORTAL_METADATA;
+        Service service = Service.GIF_REPOSITORY;
         assertTrue(service.isValidationRequired());
+
+        // There is an index file in the root
         assertEquals(ValidationResult.OK, service.validate(path));
     }
 
     @Test
-    public void testQortalMetadataMissingKeys() throws IOException {
-        // Metadata is to describe an arbitrary resource (title, description, tags, etc)
-        String dataString = "{\"description\":\"Test description\", \"tags\":[\"test\"]}";
+    public void testValidateMultiLayerGifRepository() throws IOException {
+        // Generate some random data
+        byte[] data = new byte[1024];
+        new Random().nextBytes(data);
 
-        // Write to temp path
-        Path path = Files.createTempFile("testQortalMetadataMissingKeys", null);
+        // Write the data to several files in a temp path
+        Path path = Files.createTempDirectory("testValidateMultiLayerGifRepository");
         path.toFile().deleteOnExit();
-        Files.write(path, dataString.getBytes(), StandardOpenOption.CREATE);
+        Files.write(Paths.get(path.toString(), "image1.gif"), data, StandardOpenOption.CREATE);
 
-        Service service = Service.QORTAL_METADATA;
+        Path subdirectory = Paths.get(path.toString(), "subdirectory");
+        Files.createDirectories(subdirectory);
+        Files.write(Paths.get(subdirectory.toString(), "image2.gif"), data, StandardOpenOption.CREATE);
+        Files.write(Paths.get(subdirectory.toString(), "image3.gif"), data, StandardOpenOption.CREATE);
+
+        Service service = Service.GIF_REPOSITORY;
         assertTrue(service.isValidationRequired());
-        assertEquals(ValidationResult.MISSING_KEYS, service.validate(path));
+
+        // There is an index file in the root
+        assertEquals(ValidationResult.DIRECTORIES_NOT_ALLOWED, service.validate(path));
     }
 
     @Test
-    public void testQortalMetadataTooLarge() throws IOException {
-        // Metadata is to describe an arbitrary resource (title, description, tags, etc)
-        String dataString = "{\"title\":\"Test Title\", \"description\":\"Test description\", \"tags\":[\"test\"]}";
+    public void testValidateEmptyGifRepository() throws IOException {
+        Path path = Files.createTempDirectory("testValidateEmptyGifRepository");
 
-        // Generate some large data to go along with it
-        int largeDataSize = 11*1024; // Larger than allowed 10kiB
-        byte[] largeData = new byte[largeDataSize];
-        new Random().nextBytes(largeData);
-
-        // Write to temp path
-        Path path = Files.createTempDirectory("testQortalMetadataTooLarge");
-        path.toFile().deleteOnExit();
-        Files.write(Paths.get(path.toString(), "data"), dataString.getBytes(), StandardOpenOption.CREATE);
-        Files.write(Paths.get(path.toString(), "large_data"), largeData, StandardOpenOption.CREATE);
-
-        Service service = Service.QORTAL_METADATA;
+        Service service = Service.GIF_REPOSITORY;
         assertTrue(service.isValidationRequired());
-        assertEquals(ValidationResult.EXCEEDS_SIZE_LIMIT, service.validate(path));
+
+        // There is an index file in the root
+        assertEquals(ValidationResult.MISSING_DATA, service.validate(path));
     }
 
     @Test
-    public void testMultipleFileMetadata() throws IOException {
-        // Metadata is to describe an arbitrary resource (title, description, tags, etc)
-        String dataString = "{\"title\":\"Test Title\", \"description\":\"Test description\", \"tags\":[\"test\"]}";
+    public void testValidateInvalidGifRepository() throws IOException {
+        // Generate some random data
+        byte[] data = new byte[1024];
+        new Random().nextBytes(data);
 
-        // Generate some large data to go along with it
-        int otherDataSize = 1024; // Smaller than 10kiB limit
-        byte[] otherData = new byte[otherDataSize];
-        new Random().nextBytes(otherData);
-
-        // Write to temp path
-        Path path = Files.createTempDirectory("testMultipleFileMetadata");
+        // Write the data to several files in a temp path
+        Path path = Files.createTempDirectory("testValidateInvalidGifRepository");
         path.toFile().deleteOnExit();
-        Files.write(Paths.get(path.toString(), "data"), dataString.getBytes(), StandardOpenOption.CREATE);
-        Files.write(Paths.get(path.toString(), "other_data"), otherData, StandardOpenOption.CREATE);
+        Files.write(Paths.get(path.toString(), "image1.gif"), data, StandardOpenOption.CREATE);
+        Files.write(Paths.get(path.toString(), "image2.gif"), data, StandardOpenOption.CREATE);
+        Files.write(Paths.get(path.toString(), "image3.jpg"), data, StandardOpenOption.CREATE); // Invalid extension
 
-        Service service = Service.QORTAL_METADATA;
+        Service service = Service.GIF_REPOSITORY;
         assertTrue(service.isValidationRequired());
 
-        // There are multiple files, so we don't know which one to parse as JSON
-        assertEquals(ValidationResult.MISSING_KEYS, service.validate(path));
+        // There is an index file in the root
+        assertEquals(ValidationResult.INVALID_FILE_EXTENSION, service.validate(path));
     }
 
 }

src/test/java/org/qortal/test/common/AccountUtils.java

@@ -49,10 +49,10 @@ public class AccountUtils {
 	public static TransactionData createRewardShare(Repository repository, String minter, String recipient, int sharePercent) throws DataException {
 		PrivateKeyAccount mintingAccount = Common.getTestAccount(repository, minter);
 		PrivateKeyAccount recipientAccount = Common.getTestAccount(repository, recipient);
-		return createRewardShare(repository, mintingAccount, recipientAccount, sharePercent);
+		return createRewardShare(repository, mintingAccount, recipientAccount, sharePercent, fee);
 	}
 
-	public static TransactionData createRewardShare(Repository repository, PrivateKeyAccount mintingAccount, PrivateKeyAccount recipientAccount, int sharePercent) throws DataException {
+	public static TransactionData createRewardShare(Repository repository, PrivateKeyAccount mintingAccount, PrivateKeyAccount recipientAccount, int sharePercent, long fee) throws DataException {
 		byte[] reference = mintingAccount.getLastReference();
 		long timestamp = repository.getTransactionRepository().fromSignature(reference).getTimestamp() + 1;
 
@@ -78,7 +78,7 @@ public class AccountUtils {
 	}
 
 	public static byte[] rewardShare(Repository repository, PrivateKeyAccount minterAccount, PrivateKeyAccount recipientAccount, int sharePercent) throws DataException {
-		TransactionData transactionData = createRewardShare(repository, minterAccount, recipientAccount, sharePercent);
+		TransactionData transactionData = createRewardShare(repository, minterAccount, recipientAccount, sharePercent, fee);
 
 		TransactionUtils.signAndMint(repository, transactionData, minterAccount);
 		byte[] rewardSharePrivateKey = minterAccount.getRewardSharePrivateKey(recipientAccount.getPublicKey());
@@ -124,8 +124,6 @@ public class AccountUtils {
 		long timestamp = System.currentTimeMillis();
 		byte[] timestampBytes = Longs.toByteArray(timestamp);
 
-		final boolean mempowActive = timestamp >= BlockChain.getInstance().getOnlineAccountsMemoryPoWTimestamp();
-
 		for (int a = 0; a < numAccounts; ++a) {
 			byte[] privateKey = new byte[Transformer.PUBLIC_KEY_LENGTH];
 			SECURE_RANDOM.nextBytes(privateKey);
@@ -135,7 +133,7 @@ public class AccountUtils {
 
 			byte[] signature = signForAggregation(privateKey, timestampBytes);
 
-			Integer nonce = mempowActive ? new Random().nextInt(500000) : null;
+			Integer nonce = new Random().nextInt(500000);
 
 			onlineAccounts.add(new OnlineAccountData(timestamp, signature, publicKey, nonce));
 		}

src/test/java/org/qortal/test/group/DevGroupAdminTests.java

@@ -0,0 +1,388 @@
+package org.qortal.test.group;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.qortal.account.PrivateKeyAccount;
+import org.qortal.data.transaction.*;
+import org.qortal.group.Group;
+import org.qortal.group.Group.ApprovalThreshold;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.test.common.BlockUtils;
+import org.qortal.test.common.Common;
+import org.qortal.test.common.GroupUtils;
+import org.qortal.test.common.TransactionUtils;
+import org.qortal.test.common.transaction.TestTransaction;
+import org.qortal.transaction.Transaction;
+import org.qortal.transaction.Transaction.ValidationResult;
+import org.qortal.utils.Base58;
+
+import static org.junit.Assert.*;
+
+/**
+ * Dev group admin tests
+ *
+ * The dev group (ID 1) is owned by the null account with public key 11111111111111111111111111111111
+ * To regain access to otherwise blocked owner-based rules, it has different validation logic
+ * which applies to groups with this same null owner.
+ *
+ * The main difference is that approval is required for certain transaction types relating to
+ * null-owned groups. This allows existing admins to approve updates to the group (using group's
+ * approval threshold) instead of these actions being performed by the owner.
+ *
+ * Since these apply to all null-owned groups, this allows anyone to update their group to
+ * the null owner if they want to take advantage of this decentralized approval system.
+ *
+ * Currently, the affected transaction types are:
+ * - AddGroupAdminTransaction
+ * - RemoveGroupAdminTransaction
+ *
+ * This same approach could ultimately be applied to other group transactions too.
+ */
+public class DevGroupAdminTests extends Common {
+
+	private static final int DEV_GROUP_ID = 1;
+
+	@Before
+	public void beforeTest() throws DataException {
+		Common.useDefaultSettings();
+	}
+
+	@After
+	public void afterTest() throws DataException {
+		Common.orphanCheck();
+	}
+
+	@Test
+	public void testGroupKickMember() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount alice = Common.getTestAccount(repository, "alice");
+			PrivateKeyAccount bob = Common.getTestAccount(repository, "bob");
+
+			// Dev group
+			int groupId = DEV_GROUP_ID;
+
+			// Confirm Bob is not a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Attempt to kick Bob
+			ValidationResult result = groupKick(repository, alice, groupId, bob.getAddress());
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Alice to invite Bob, as it's a closed group
+			groupInvite(repository, alice, groupId, bob.getAddress(), 3600);
+
+			// Bob to join
+			joinGroup(repository, bob, groupId);
+
+			// Confirm Bob now a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+
+			// Attempt to kick Bob
+			result = groupKick(repository, alice, groupId, bob.getAddress());
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Confirm Bob no longer a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Orphan last block
+			BlockUtils.orphanLastBlock(repository);
+
+			// Confirm Bob now a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+		}
+	}
+
+	@Test
+	public void testGroupKickAdmin() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount alice = Common.getTestAccount(repository, "alice");
+			PrivateKeyAccount bob = Common.getTestAccount(repository, "bob");
+
+			// Dev group
+			int groupId = DEV_GROUP_ID;
+
+			// Confirm Bob is not a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Alice to invite Bob, as it's a closed group
+			groupInvite(repository, alice, groupId, bob.getAddress(), 3600);
+
+			// Bob to join
+			joinGroup(repository, bob, groupId);
+
+			// Confirm Bob now a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+
+			// Promote Bob to admin
+			TransactionData addGroupAdminTransactionData = addGroupAdmin(repository, alice, groupId, bob.getAddress());
+
+			// Confirm transaction needs approval, and hasn't been approved
+			Transaction.ApprovalStatus approvalStatus = GroupUtils.getApprovalStatus(repository, addGroupAdminTransactionData.getSignature());
+			assertEquals("incorrect transaction approval status", Transaction.ApprovalStatus.PENDING, approvalStatus);
+
+			// Have Alice approve Bob's approval-needed transaction
+			GroupUtils.approveTransaction(repository, "alice", addGroupAdminTransactionData.getSignature(), true);
+
+			// Mint a block so that the transaction becomes approved
+			BlockUtils.mintBlock(repository);
+
+			// Confirm transaction is approved
+			approvalStatus = GroupUtils.getApprovalStatus(repository, addGroupAdminTransactionData.getSignature());
+			assertEquals("incorrect transaction approval status", Transaction.ApprovalStatus.APPROVED, approvalStatus);
+
+			// Confirm Bob is now admin
+			assertTrue(isAdmin(repository, bob.getAddress(), groupId));
+
+			// Attempt to kick Bob
+			ValidationResult result = groupKick(repository, alice, groupId, bob.getAddress());
+			// Shouldn't be allowed
+			assertEquals(ValidationResult.INVALID_GROUP_OWNER, result);
+
+			// Confirm Bob is still a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+
+			// Confirm Bob still an admin
+			assertTrue(isAdmin(repository, bob.getAddress(), groupId));
+
+			// Orphan last block
+			BlockUtils.orphanLastBlock(repository);
+
+			// Confirm Bob no longer an admin (ADD_GROUP_ADMIN no longer approved)
+			assertFalse(isAdmin(repository, bob.getAddress(), groupId));
+
+			// Have Alice try to kick herself!
+			result = groupKick(repository, alice, groupId, alice.getAddress());
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Have Bob try to kick Alice
+			result = groupKick(repository, bob, groupId, alice.getAddress());
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+		}
+	}
+
+	@Test
+	public void testGroupBanMember() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount alice = Common.getTestAccount(repository, "alice");
+			PrivateKeyAccount bob = Common.getTestAccount(repository, "bob");
+
+			// Dev group
+			int groupId = DEV_GROUP_ID;
+
+			// Confirm Bob is not a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Attempt to cancel non-existent Bob ban
+			ValidationResult result = cancelGroupBan(repository, alice, groupId, bob.getAddress());
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Attempt to ban Bob
+			result = groupBan(repository, alice, groupId, bob.getAddress());
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Bob attempts to rejoin
+			result = joinGroup(repository, bob, groupId);
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Orphan last block (Bob ban)
+			BlockUtils.orphanLastBlock(repository);
+			// Delete unconfirmed group-ban transaction
+			TransactionUtils.deleteUnconfirmedTransactions(repository);
+
+			// Confirm Bob is not a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Alice to invite Bob, as it's a closed group
+			groupInvite(repository, alice, groupId, bob.getAddress(), 3600);
+
+			// Bob to join
+			result = joinGroup(repository, bob, groupId);
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Confirm Bob now a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+
+			// Attempt to ban Bob
+			result = groupBan(repository, alice, groupId, bob.getAddress());
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Confirm Bob no longer a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Bob attempts to rejoin
+			result = joinGroup(repository, bob, groupId);
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Cancel Bob's ban
+			result = cancelGroupBan(repository, alice, groupId, bob.getAddress());
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Bob attempts to rejoin
+			result = joinGroup(repository, bob, groupId);
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Orphan last block (Bob join)
+			BlockUtils.orphanLastBlock(repository);
+			// Delete unconfirmed join-group transaction
+			TransactionUtils.deleteUnconfirmedTransactions(repository);
+
+			// Orphan last block (Cancel Bob ban)
+			BlockUtils.orphanLastBlock(repository);
+			// Delete unconfirmed cancel-ban transaction
+			TransactionUtils.deleteUnconfirmedTransactions(repository);
+
+			// Bob attempts to rejoin
+			result = joinGroup(repository, bob, groupId);
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Orphan last block (Bob ban)
+			BlockUtils.orphanLastBlock(repository);
+			// Delete unconfirmed group-ban transaction
+			TransactionUtils.deleteUnconfirmedTransactions(repository);
+
+			// Confirm Bob now a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+		}
+	}
+
+	@Test
+	public void testGroupBanAdmin() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount alice = Common.getTestAccount(repository, "alice");
+			PrivateKeyAccount bob = Common.getTestAccount(repository, "bob");
+
+			// Dev group
+			int groupId = DEV_GROUP_ID;
+
+			// Confirm Bob is not a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Alice to invite Bob, as it's a closed group
+			groupInvite(repository, alice, groupId, bob.getAddress(), 3600);
+
+			// Bob to join
+			ValidationResult result = joinGroup(repository, bob, groupId);
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Promote Bob to admin
+			TransactionData addGroupAdminTransactionData = addGroupAdmin(repository, alice, groupId, bob.getAddress());
+
+			// Confirm transaction needs approval, and hasn't been approved
+			Transaction.ApprovalStatus approvalStatus = GroupUtils.getApprovalStatus(repository, addGroupAdminTransactionData.getSignature());
+			assertEquals("incorrect transaction approval status", Transaction.ApprovalStatus.PENDING, approvalStatus);
+
+			// Have Alice approve Bob's approval-needed transaction
+			GroupUtils.approveTransaction(repository, "alice", addGroupAdminTransactionData.getSignature(), true);
+
+			// Mint a block so that the transaction becomes approved
+			BlockUtils.mintBlock(repository);
+
+			// Confirm transaction is approved
+			approvalStatus = GroupUtils.getApprovalStatus(repository, addGroupAdminTransactionData.getSignature());
+			assertEquals("incorrect transaction approval status", Transaction.ApprovalStatus.APPROVED, approvalStatus);
+
+			// Confirm Bob is now admin
+			assertTrue(isAdmin(repository, bob.getAddress(), groupId));
+
+			// Attempt to ban Bob
+			result = groupBan(repository, alice, groupId, bob.getAddress());
+			// .. but we can't, because Bob is an admin and the group has no owner
+			assertEquals(ValidationResult.INVALID_GROUP_OWNER, result);
+
+			// Confirm Bob still a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+
+			// ... and still an admin
+			assertTrue(isAdmin(repository, bob.getAddress(), groupId));
+
+			// Have Alice try to ban herself!
+			result = groupBan(repository, alice, groupId, alice.getAddress());
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Have Bob try to ban Alice
+			result = groupBan(repository, bob, groupId, alice.getAddress());
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+		}
+	}
+
+
+	private ValidationResult joinGroup(Repository repository, PrivateKeyAccount joiner, int groupId) throws DataException {
+		JoinGroupTransactionData transactionData = new JoinGroupTransactionData(TestTransaction.generateBase(joiner), groupId);
+		ValidationResult result = TransactionUtils.signAndImport(repository, transactionData, joiner);
+
+		if (result == ValidationResult.OK)
+			BlockUtils.mintBlock(repository);
+
+		return result;
+	}
+
+	private void groupInvite(Repository repository, PrivateKeyAccount admin, int groupId, String invitee, int timeToLive) throws DataException {
+		GroupInviteTransactionData transactionData = new GroupInviteTransactionData(TestTransaction.generateBase(admin), groupId, invitee, timeToLive);
+		TransactionUtils.signAndMint(repository, transactionData, admin);
+	}
+
+	private ValidationResult groupKick(Repository repository, PrivateKeyAccount admin, int groupId, String member) throws DataException {
+		GroupKickTransactionData transactionData = new GroupKickTransactionData(TestTransaction.generateBase(admin), groupId, member, "testing");
+		ValidationResult result = TransactionUtils.signAndImport(repository, transactionData, admin);
+
+		if (result == ValidationResult.OK)
+			BlockUtils.mintBlock(repository);
+
+		return result;
+	}
+
+	private ValidationResult groupBan(Repository repository, PrivateKeyAccount admin, int groupId, String member) throws DataException {
+		GroupBanTransactionData transactionData = new GroupBanTransactionData(TestTransaction.generateBase(admin), groupId, member, "testing", 0);
+		ValidationResult result = TransactionUtils.signAndImport(repository, transactionData, admin);
+
+		if (result == ValidationResult.OK)
+			BlockUtils.mintBlock(repository);
+
+		return result;
+	}
+
+	private ValidationResult cancelGroupBan(Repository repository, PrivateKeyAccount admin, int groupId, String member) throws DataException {
+		CancelGroupBanTransactionData transactionData = new CancelGroupBanTransactionData(TestTransaction.generateBase(admin), groupId, member);
+		ValidationResult result = TransactionUtils.signAndImport(repository, transactionData, admin);
+
+		if (result == ValidationResult.OK)
+			BlockUtils.mintBlock(repository);
+
+		return result;
+	}
+
+	private TransactionData addGroupAdmin(Repository repository, PrivateKeyAccount owner, int groupId, String member) throws DataException {
+		AddGroupAdminTransactionData transactionData = new AddGroupAdminTransactionData(TestTransaction.generateBase(owner), groupId, member);
+		transactionData.setTxGroupId(groupId);
+		TransactionUtils.signAndMint(repository, transactionData, owner);
+		return transactionData;
+	}
+
+	private boolean isMember(Repository repository, String address, int groupId) throws DataException {
+		return repository.getGroupRepository().memberExists(groupId, address);
+	}
+
+	private boolean isAdmin(Repository repository, String address, int groupId) throws DataException {
+		return repository.getGroupRepository().adminExists(groupId, address);
+	}
+
+}

src/test/resources/test-chain-v2-block-timestamps.json

@@ -14,6 +14,7 @@
 	"founderEffectiveMintingLevel": 10,
 	"onlineAccountSignaturesMinLifetime": 3600000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 100 },
 		{ "height": 11, "reward": 10 },
@@ -69,7 +70,10 @@
 		"calcChainWeightTimestamp": 0,
 		"transactionV5Timestamp": 0,
 		"transactionV6Timestamp": 9999999999999,
-		"disableReferenceTimestamp": 9999999999999
+		"disableReferenceTimestamp": 9999999999999,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 999999999
 	},
 	"genesisInfo": {
 		"version": 4,

src/test/resources/test-chain-v2-disable-reference.json

@@ -18,6 +18,7 @@
 	"founderEffectiveMintingLevel": 10,
 	"onlineAccountSignaturesMinLifetime": 3600000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 100 },
 		{ "height": 11, "reward": 10 },
@@ -72,7 +73,10 @@
 		"calcChainWeightTimestamp": 0,
 		"transactionV5Timestamp": 0,
 		"transactionV6Timestamp": 0,
-		"disableReferenceTimestamp": 0
+		"disableReferenceTimestamp": 0,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 999999999
 	},
 	"genesisInfo": {
 		"version": 4,

src/test/resources/test-chain-v2-founder-rewards.json

@@ -19,6 +19,7 @@
 	"onlineAccountSignaturesMinLifetime": 3600000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
 	"onlineAccountsModulusV2Timestamp": 9999999999999,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 100 },
 		{ "height": 11, "reward": 10 },
@@ -73,7 +74,10 @@
 		"calcChainWeightTimestamp": 0,
 		"transactionV5Timestamp": 0,
 		"transactionV6Timestamp": 0,
-		"disableReferenceTimestamp": 9999999999999
+		"disableReferenceTimestamp": 9999999999999,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 999999999
 	},
 	"genesisInfo": {
 		"version": 4,

src/test/resources/test-chain-v2-leftover-reward.json

@@ -19,6 +19,7 @@
 	"onlineAccountSignaturesMinLifetime": 3600000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
 	"onlineAccountsModulusV2Timestamp": 9999999999999,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 100 },
 		{ "height": 11, "reward": 10 },
@@ -73,7 +74,10 @@
 		"calcChainWeightTimestamp": 0,
 		"transactionV5Timestamp": 0,
 		"transactionV6Timestamp": 0,
-		"disableReferenceTimestamp": 9999999999999
+		"disableReferenceTimestamp": 9999999999999,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 999999999
 	},
 	"genesisInfo": {
 		"version": 4,

src/test/resources/test-chain-v2-minting.json

@@ -19,6 +19,7 @@
 	"onlineAccountSignaturesMinLifetime": 3600000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
 	"onlineAccountsModulusV2Timestamp": 9999999999999,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 100 },
 		{ "height": 11, "reward": 10 },
@@ -73,7 +74,10 @@
 		"calcChainWeightTimestamp": 0,
 		"transactionV5Timestamp": 0,
 		"transactionV6Timestamp": 0,
-		"disableReferenceTimestamp": 9999999999999
+		"disableReferenceTimestamp": 9999999999999,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 999999999
 	},
 	"genesisInfo": {
 		"version": 4,

src/test/resources/test-chain-v2-qora-holder-extremes.json

@@ -19,6 +19,7 @@
 	"onlineAccountSignaturesMinLifetime": 3600000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
 	"onlineAccountsModulusV2Timestamp": 9999999999999,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 100 },
 		{ "height": 11, "reward": 10 },
@@ -73,7 +74,10 @@
 		"calcChainWeightTimestamp": 0,
 		"transactionV5Timestamp": 0,
 		"transactionV6Timestamp": 0,
-		"disableReferenceTimestamp": 9999999999999
+		"disableReferenceTimestamp": 9999999999999,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 999999999
 	},
 	"genesisInfo": {
 		"version": 4,

src/test/resources/test-chain-v2-qora-holder-reduction.json

@@ -19,6 +19,7 @@
 	"onlineAccountSignaturesMinLifetime": 3600000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
 	"onlineAccountsModulusV2Timestamp": 9999999999999,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 100 },
 		{ "height": 11, "reward": 10 },
@@ -74,7 +75,10 @@
 		"transactionV5Timestamp": 0,
 		"transactionV6Timestamp": 0,
 		"disableReferenceTimestamp": 9999999999999,
-		"aggregateSignatureTimestamp": 0
+		"aggregateSignatureTimestamp": 0,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 999999999
 	},
 	"genesisInfo": {
 		"version": 4,

src/test/resources/test-chain-v2-qora-holder.json

@@ -19,6 +19,7 @@
 	"onlineAccountSignaturesMinLifetime": 3600000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
 	"onlineAccountsModulusV2Timestamp": 9999999999999,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 100 },
 		{ "height": 11, "reward": 10 },
@@ -73,7 +74,10 @@
 		"calcChainWeightTimestamp": 0,
 		"transactionV5Timestamp": 0,
 		"transactionV6Timestamp": 0,
-		"disableReferenceTimestamp": 9999999999999
+		"disableReferenceTimestamp": 9999999999999,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 999999999
 	},
 	"genesisInfo": {
 		"version": 4,

src/test/resources/test-chain-v2-reward-levels.json

@@ -19,6 +19,7 @@
 	"onlineAccountSignaturesMinLifetime": 3600000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
 	"onlineAccountsModulusV2Timestamp": 9999999999999,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 100 },
 		{ "height": 11, "reward": 10 },
@@ -73,7 +74,10 @@
 		"calcChainWeightTimestamp": 0,
 		"transactionV5Timestamp": 0,
 		"transactionV6Timestamp": 0,
-		"disableReferenceTimestamp": 9999999999999
+		"disableReferenceTimestamp": 9999999999999,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 999999999
 	},
 	"genesisInfo": {
 		"version": 4,

src/test/resources/test-chain-v2-reward-scaling.json

@@ -19,6 +19,7 @@
 	"onlineAccountSignaturesMinLifetime": 3600000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
 	"onlineAccountsModulusV2Timestamp": 9999999999999,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 100 },
 		{ "height": 11, "reward": 10 },
@@ -73,7 +74,10 @@
 		"calcChainWeightTimestamp": 0,
 		"transactionV5Timestamp": 0,
 		"transactionV6Timestamp": 0,
-		"disableReferenceTimestamp": 9999999999999
+		"disableReferenceTimestamp": 9999999999999,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 999999999
 	},
 	"genesisInfo": {
 		"version": 4,

src/test/resources/test-chain-v2-reward-shares.json

@@ -18,6 +18,7 @@
 	"founderEffectiveMintingLevel": 10,
 	"onlineAccountSignaturesMinLifetime": 3600000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 100 },
 		{ "height": 11, "reward": 10 },
@@ -73,7 +74,10 @@
 		"newConsensusTimestamp": 0,
 		"transactionV5Timestamp": 0,
 		"transactionV6Timestamp": 0,
-		"disableReferenceTimestamp": 9999999999999
+		"disableReferenceTimestamp": 9999999999999,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 999999999
 	},
 	"genesisInfo": {
 		"version": 4,

src/test/resources/test-chain-v2-self-sponsorship-algo.json

@@ -0,0 +1,114 @@
+{
+	"isTestChain": true,
+	"blockTimestampMargin": 500,
+	"transactionExpiryPeriod": 86400000,
+	"maxBlockSize": 2097152,
+	"maxBytesPerUnitFee": 0,
+	"unitFee": "0.00000001",
+	"nameRegistrationUnitFees": [
+		{ "timestamp": 1645372800000, "fee": "5" }
+	],
+	"requireGroupForApproval": false,
+	"minAccountLevelToRewardShare": 5,
+	"maxRewardSharesPerFounderMintingAccount": 20,
+	"maxRewardSharesByTimestamp": [
+		{ "timestamp": 0, "maxShares": 20 },
+		{ "timestamp": 9999999999999, "maxShares": 3 }
+	],
+	"founderEffectiveMintingLevel": 10,
+	"onlineAccountSignaturesMinLifetime": 3600000,
+	"onlineAccountSignaturesMaxLifetime": 86400000,
+	"onlineAccountsModulusV2Timestamp": 9999999999999,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
+	"rewardsByHeight": [
+		{ "height": 1, "reward": 100 },
+		{ "height": 11, "reward": 10 },
+		{ "height": 21, "reward": 1 }
+	],
+	"sharesByLevelV1": [
+		{ "id": 1, "levels": [ 1, 2 ], "share": 0.05 },
+		{ "id": 2, "levels": [ 3, 4 ], "share": 0.10 },
+		{ "id": 3, "levels": [ 5, 6 ], "share": 0.15 },
+		{ "id": 4, "levels": [ 7, 8 ], "share": 0.20 },
+		{ "id": 5, "levels": [ 9, 10 ], "share": 0.25 }
+	],
+	"sharesByLevelV2": [
+		{ "id": 1, "levels": [ 1, 2 ], "share": 0.06 },
+		{ "id": 2, "levels": [ 3, 4 ], "share": 0.13 },
+		{ "id": 3, "levels": [ 5, 6 ], "share": 0.19 },
+		{ "id": 4, "levels": [ 7, 8 ], "share": 0.26 },
+		{ "id": 5, "levels": [ 9, 10 ], "share": 0.32 }
+	],
+	"qoraHoldersShareByHeight": [
+		{ "height": 1, "share": 0.20 },
+		{ "height": 1000000, "share": 0.01 }
+	],
+	"qoraPerQortReward": 250,
+	"minAccountsToActivateShareBin": 30,
+	"shareBinActivationMinLevel": 7,
+	"blocksNeededByLevel": [ 5, 20, 30, 40, 50, 60, 18, 80, 90, 100 ],
+	"blockTimingsByHeight": [
+		{ "height": 1, "target": 60000, "deviation": 30000, "power": 0.2 }
+	],
+	"ciyamAtSettings": {
+		"feePerStep": "0.0001",
+		"maxStepsPerRound": 500,
+		"stepsPerFunctionCall": 10,
+		"minutesPerBlock": 1
+	},
+	"featureTriggers": {
+		"messageHeight": 0,
+		"atHeight": 0,
+		"assetsTimestamp": 0,
+		"votingTimestamp": 0,
+		"arbitraryTimestamp": 0,
+		"powfixTimestamp": 0,
+		"qortalTimestamp": 0,
+		"newAssetPricingTimestamp": 0,
+		"groupApprovalTimestamp": 0,
+		"atFindNextTransactionFix": 0,
+		"newBlockSigHeight": 999999,
+		"shareBinFix": 999999,
+		"sharesByLevelV2Height": 999999,
+		"rewardShareLimitTimestamp": 9999999999999,
+		"calcChainWeightTimestamp": 0,
+		"transactionV5Timestamp": 0,
+		"transactionV6Timestamp": 0,
+		"disableReferenceTimestamp": 9999999999999,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 20
+	},
+	"genesisInfo": {
+		"version": 4,
+		"timestamp": 0,
+		"transactions": [
+			{ "type": "ISSUE_ASSET", "assetName": "QORT", "description": "QORT native coin", "data": "", "quantity": 0, "isDivisible": true, "fee": 0 },
+			{ "type": "ISSUE_ASSET", "assetName": "Legacy-QORA", "description": "Representative legacy QORA", "quantity": 0, "isDivisible": true, "data": "{}", "isUnspendable": true },
+			{ "type": "ISSUE_ASSET", "assetName": "QORT-from-QORA", "description": "QORT gained from holding legacy QORA", "quantity": 0, "isDivisible": true, "data": "{}", "isUnspendable": true },
+
+			{ "type": "GENESIS", "recipient": "QgV4s3xnzLhVBEJxcYui4u4q11yhUHsd9v", "amount": "1000000000" },
+			{ "type": "GENESIS", "recipient": "QixPbJUwsaHsVEofJdozU9zgVqkK6aYhrK", "amount": "1000000" },
+			{ "type": "GENESIS", "recipient": "QaUpHNhT3Ygx6avRiKobuLdusppR5biXjL", "amount": "1000000" },
+			{ "type": "GENESIS", "recipient": "Qci5m9k4rcwe4ruKrZZQKka4FzUUMut3er", "amount": "1000000" },
+
+			{ "type": "CREATE_GROUP", "creatorPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "groupName": "dev-group", "description": "developer group", "isOpen": false, "approvalThreshold": "PCT100", "minimumBlockDelay": 0, "maximumBlockDelay": 1440 },
+
+			{ "type": "UPDATE_GROUP", "ownerPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "groupId": 1, "newOwner": "QdSnUy6sUiEnaN87dWmE92g1uQjrvPgrWG", "newDescription": "developer group", "newIsOpen": false, "newApprovalThreshold": "PCT40", "minimumBlockDelay": 10, "maximumBlockDelay": 1440 },
+
+			{ "type": "ISSUE_ASSET", "issuerPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "assetName": "TEST", "description": "test asset", "data": "", "quantity": "1000000", "isDivisible": true, "fee": 0 },
+			{ "type": "ISSUE_ASSET", "issuerPublicKey": "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry", "assetName": "OTHER", "description": "other test asset", "data": "", "quantity": "1000000", "isDivisible": true, "fee": 0 },
+			{ "type": "ISSUE_ASSET", "issuerPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "assetName": "GOLD", "description": "gold test asset", "data": "", "quantity": "1000000", "isDivisible": true, "fee": 0 },
+
+			{ "type": "ACCOUNT_FLAGS", "target": "QgV4s3xnzLhVBEJxcYui4u4q11yhUHsd9v", "andMask": -1, "orMask": 1, "xorMask": 0 },
+			{ "type": "REWARD_SHARE", "minterPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "recipient": "QgV4s3xnzLhVBEJxcYui4u4q11yhUHsd9v", "rewardSharePublicKey": "7PpfnvLSG7y4HPh8hE7KoqAjLCkv7Ui6xw4mKAkbZtox", "sharePercent": "100" },
+
+			{ "type": "ACCOUNT_LEVEL", "target": "QixPbJUwsaHsVEofJdozU9zgVqkK6aYhrK", "level": 5 },
+			{ "type": "REWARD_SHARE", "minterPublicKey": "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry", "recipient": "QixPbJUwsaHsVEofJdozU9zgVqkK6aYhrK", "rewardSharePublicKey": "CcABzvk26TFEHG7Yok84jxyd4oBtLkx8RJdGFVz2csvp", "sharePercent": 100 },
+
+			{ "type": "ACCOUNT_LEVEL", "target": "Qci5m9k4rcwe4ruKrZZQKka4FzUUMut3er", "level": 5 },
+			{ "type": "ACCOUNT_LEVEL", "target": "QaUpHNhT3Ygx6avRiKobuLdusppR5biXjL", "level": 5 },
+			{ "type": "ACCOUNT_LEVEL", "target": "Qci5m9k4rcwe4ruKrZZQKka4FzUUMut3er", "level": 6 }
+		]
+	}
+}

src/test/resources/test-chain-v2.json

@@ -19,6 +19,7 @@
 	"onlineAccountSignaturesMinLifetime": 3600000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
 	"onlineAccountsModulusV2Timestamp": 9999999999999,
+	"selfSponsorshipAlgoV1SnapshotTimestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 100 },
 		{ "height": 11, "reward": 10 },
@@ -73,7 +74,10 @@
 		"calcChainWeightTimestamp": 0,
 		"transactionV5Timestamp": 0,
 		"transactionV6Timestamp": 0,
-		"disableReferenceTimestamp": 9999999999999
+		"disableReferenceTimestamp": 9999999999999,
+		"increaseOnlineAccountsDifficultyTimestamp": 9999999999999,
+		"onlineAccountMinterLevelValidationHeight": 0,
+		"selfSponsorshipAlgoV1Height": 999999999
 	},
 	"genesisInfo": {
 		"version": 4,
@@ -90,6 +94,8 @@
 
 			{ "type": "CREATE_GROUP", "creatorPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "groupName": "dev-group", "description": "developer group", "isOpen": false, "approvalThreshold": "PCT100", "minimumBlockDelay": 0, "maximumBlockDelay": 1440 },
 
+			{ "type": "UPDATE_GROUP", "ownerPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "groupId": 1, "newOwner": "QdSnUy6sUiEnaN87dWmE92g1uQjrvPgrWG", "newDescription": "developer group", "newIsOpen": false, "newApprovalThreshold": "PCT40", "minimumBlockDelay": 10, "maximumBlockDelay": 1440 },
+
 			{ "type": "ISSUE_ASSET", "issuerPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "assetName": "TEST", "description": "test asset", "data": "", "quantity": "1000000", "isDivisible": true, "fee": 0 },
 			{ "type": "ISSUE_ASSET", "issuerPublicKey": "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry", "assetName": "OTHER", "description": "other test asset", "data": "", "quantity": "1000000", "isDivisible": true, "fee": 0 },
 			{ "type": "ISSUE_ASSET", "issuerPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "assetName": "GOLD", "description": "gold test asset", "data": "", "quantity": "1000000", "isDivisible": true, "fee": 0 },

src/test/resources/test-settings-v2-self-sponsorship-algo.json

@@ -0,0 +1,20 @@
+{
+  "repositoryPath": "testdb",
+  "bitcoinNet": "TEST3",
+  "litecoinNet": "TEST3",
+  "restrictedApi": false,
+  "blockchainConfig": "src/test/resources/test-chain-v2-self-sponsorship-algo.json",
+  "exportPath": "qortal-backup-test",
+  "bootstrap": false,
+  "wipeUnconfirmedOnStart": false,
+  "testNtpOffset": 0,
+  "minPeers": 0,
+  "pruneBlockLimit": 100,
+  "bootstrapFilenamePrefix": "test-",
+  "dataPath": "data-test",
+  "tempDataPath": "data-test/_temp",
+  "listsPath": "lists-test",
+  "storagePolicy": "FOLLOWED_OR_VIEWED",
+  "maxStorageCapacity": 104857600,
+  "arrrDefaultBirthday": 1900000
+}

tools/approve-dev-transaction.sh

@@ -0,0 +1,97 @@
+#!/usr/bin/env bash
+
+port=12391
+if [ $# -gt 0 -a "$1" = "-t" ]; then
+	port=62391
+fi
+
+printf "Searching for auto-update transactions to approve...\n";
+
+tx=$( curl --silent --url "http://localhost:${port}/transactions/search?txGroupId=1&txType=ADD_GROUP_ADMIN&txType=REMOVE_GROUP_ADMIN&confirmationStatus=CONFIRMED&limit=1&reverse=true" );
+if fgrep --silent '"approvalStatus":"PENDING"' <<< "${tx}"; then
+	true
+else
+	echo "Can't find any pending transactions"
+	exit
+fi
+
+sig=$( perl -n -e 'print $1 if m/"signature":"(\w+)"/' <<< "${tx}" )
+if [ -z "${sig}" ]; then
+	printf "Can't find transaction signature in JSON:\n%s\n" "${tx}"
+	exit
+fi
+
+printf "Found transaction %s\n" $sig;
+
+printf "\nPaste your dev account private key:\n";
+IFS=
+read -s privkey
+printf "\n"
+
+# Convert to public key
+pubkey=$( curl --silent --url "http://localhost:${port}/utils/publickey" --data @- <<< "${privkey}" );
+if egrep -v --silent '^\w{44,46}$' <<< "${pubkey}"; then
+	printf "Invalid response from API - was your private key correct?\n%s\n" "${pubkey}"
+	exit
+fi
+printf "Your public key: %s\n" ${pubkey}
+
+# Convert to address
+address=$( curl --silent --url "http://localhost:${port}/addresses/convert/${pubkey}" );
+printf "Your address: %s\n" ${address}
+
+# Grab last reference
+lastref=$( curl --silent --url "http://localhost:${port}/addresses/lastreference/{$address}" );
+printf "Your last reference: %s\n" ${lastref}
+
+# Build GROUP_APPROVAL transaction
+timestamp=$( date +%s )000
+tx_json=$( cat <<TX_END
+{
+  "timestamp": ${timestamp},
+  "reference": "${lastref}",
+  "fee": 0.001,
+  "txGroupId": 0,
+  "adminPublicKey": "${pubkey}",
+  "pendingSignature": "${sig}",
+  "approval": true
+}
+TX_END
+)
+
+raw_tx=$( curl --silent --header "Content-Type: application/json" --url "http://localhost:${port}/groups/approval" --data @- <<< "${tx_json}" )
+if egrep -v --silent '^\w{100,}' <<< "${raw_tx}"; then
+	printf "Building GROUP_APPROVAL transaction failed:\n%s\n" "${raw_tx}"
+	exit
+fi
+printf "\nRaw approval tx:\n%s\n" ${raw_tx}
+
+# sign
+sign_json=$( cat <<SIGN_END
+{
+  "privateKey": "${privkey}",
+  "transactionBytes": "${raw_tx}"
+}
+SIGN_END
+)
+signed_tx=$( curl --silent --header "Content-Type: application/json" --url "http://localhost:${port}/transactions/sign" --data @- <<< "${sign_json}" )
+printf "\nSigned tx:\n%s\n" ${signed_tx}
+if egrep -v --silent '^\w{100,}' <<< "${signed_tx}"; then
+	printf "Signing GROUP_APPROVAL transaction failed:\n%s\n" "${signed_tx}"
+	exit
+fi
+
+# ready to publish?
+plural="s"
+printf "\n"
+for ((seconds = 5; seconds > 0; seconds--)); do
+	if [ "${seconds}" = "1" ]; then
+		plural=""
+	fi
+	printf "\rBroadcasting in %d second%s...(CTRL-C) to abort " $seconds $plural
+	sleep 1
+done
+
+printf "\rBroadcasting signed GROUP_APPROVAL transaction...      \n"
+result=$( curl --silent --url "http://localhost:${port}/transactions/process" --data @- <<< "${signed_tx}" )
+printf "API response:\n%s\n" "${result}"

tools/publish-auto-update-v5.pl

@@ -4,6 +4,7 @@ use strict;
 use warnings;
 use POSIX;
 use Getopt::Std;
+use File::Slurp;
 
 sub usage() {
 	die("usage: $0 [-p api-port] dev-private-key [short-commit-hash]\n");
@@ -34,6 +35,8 @@ while (<POM>) {
 }
 close(POM);
 
+my $apikey = read_file('apikey.txt');
+
 # Do we need to determine commit hash?
 unless ($commit_hash) {
 	# determine git branch
@@ -124,7 +127,7 @@ my $raw_tx = `curl --silent --url http://localhost:${port}/utils/tobase58/${raw_
 die("Can't convert raw transaction hex to base58:\n$raw_tx\n") unless $raw_tx =~ m/^\w{300,320}$/; # Roughly 305 to 320 base58 chars
 printf "\nRaw transaction (base58):\n%s\n", $raw_tx;
 
-my $computed_tx = `curl --silent -X POST --url http://localhost:${port}/arbitrary/compute -d "${raw_tx}"`;
+my $computed_tx = `curl --silent -X POST --url http://localhost:${port}/arbitrary/compute -H "X-API-KEY: ${apikey}" -d "${raw_tx}"`;
 die("Can't compute nonce for transaction:\n$computed_tx\n") unless $computed_tx =~ m/^\w{300,320}$/; # Roughly 300 to 320 base58 chars
 printf "\nRaw computed transaction (base58):\n%s\n", $computed_tx;
 

tools/tx.pl

@@ -71,9 +71,14 @@ our %TRANSACTION_TYPES = (
 	},
 	add_group_admin => {
 		url => 'groups/addadmin',
-		required => [qw(groupId member)],
+		required => [qw(groupId txGroupId member)],
 		key_name => 'ownerPublicKey',
 	},
+	remove_group_admin => {
+        url => 'groups/removeadmin',
+        required => [qw(groupId txGroupId admin)],
+        key_name => 'ownerPublicKey',
+    },
 	group_approval => {
 		url => 'groups/approval',
 		required => [qw(pendingSignature approval)],