Increase ONLINE_ACCOUNTS_MODULUS from 5 to 30 mins at a future undecided timestamp.

Note: it's important that this timestamp is set on a 1-hour boundary (such as 16:00:00) to ensure a clean switchover.

# Conflicts:
#	src/main/java/org/qortal/block/BlockChain.java

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

@@ -987,7 +987,7 @@ public class Block {
 		byte[] onlineTimestampBytes = Longs.toByteArray(onlineTimestamp);
 
 		// If this block is much older than current online timestamp, then there's no point checking current online accounts
-		List<OnlineAccountData> currentOnlineAccounts = onlineTimestamp < NTP.getTime() - OnlineAccountsManager.ONLINE_TIMESTAMP_MODULUS
+		List<OnlineAccountData> currentOnlineAccounts = onlineTimestamp < NTP.getTime() - OnlineAccountsManager.getOnlineTimestampModulus()
 				? null
 				: OnlineAccountsManager.getInstance().getOnlineAccounts();
 		List<OnlineAccountData> latestBlocksOnlineAccounts = OnlineAccountsManager.getInstance().getLatestBlocksOnlineAccounts();

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

@@ -162,6 +162,10 @@ public class BlockChain {
 	/** Maximum time to retain online account signatures (ms) for block validity checks, to allow for clock variance. */
 	private long onlineAccountSignaturesMaxLifetime;
 
+	/** Feature trigger timestamp for ONLINE_ACCOUNTS_MODULUS time interval increase. Can't use
+	 * featureTriggers because unit tests need to set this value via Reflection. */
+	private long onlineAccountsModulusV2Timestamp;
+
 	/** Settings relating to CIYAM AT feature. */
 	public static class CiyamAtSettings {
 		/** Fee per step/op-code executed. */
@@ -310,6 +314,11 @@ public class BlockChain {
 		return this.maxBlockSize;
 	}
 
+	// Online accounts
+	public long getOnlineAccountsModulusV2Timestamp() {
+		return this.onlineAccountsModulusV2Timestamp;
+	}
+
 	/** Returns true if approval-needing transaction types require a txGroupId other than NO_GROUP. */
 	public boolean getRequireGroupForApproval() {
 		return this.requireGroupForApproval;

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

@@ -50,8 +50,8 @@ public class OnlineAccountsManager extends Thread {
     // To do with online accounts list
     private static final long ONLINE_ACCOUNTS_TASKS_INTERVAL = 10 * 1000L; // ms
     private static final long ONLINE_ACCOUNTS_BROADCAST_INTERVAL = 1 * 60 * 1000L; // ms
-    public static final long ONLINE_TIMESTAMP_MODULUS = 5 * 60 * 1000L;
-    private static final long LAST_SEEN_EXPIRY_PERIOD = (ONLINE_TIMESTAMP_MODULUS * 2) + (1 * 60 * 1000L);
+    public static final long ONLINE_TIMESTAMP_MODULUS_V1 = 5 * 60 * 1000L;
+    public static final long ONLINE_TIMESTAMP_MODULUS_V2 = 30 * 60 * 1000L;
     /** How many (latest) blocks' worth of online accounts we cache */
     private static final int MAX_BLOCKS_CACHED_ONLINE_ACCOUNTS = 2;
     private static final long ONLINE_ACCOUNTS_V2_PEER_VERSION = 0x0300020000L;
@@ -116,6 +116,13 @@ public class OnlineAccountsManager extends Thread {
         this.interrupt();
     }
 
+    public static long getOnlineTimestampModulus() {
+        if (NTP.getTime() >= BlockChain.getInstance().getOnlineAccountsModulusV2Timestamp()) {
+            return ONLINE_TIMESTAMP_MODULUS_V2;
+        }
+        return ONLINE_TIMESTAMP_MODULUS_V1;
+    }
+
 
     // Online accounts import queue
 
@@ -159,7 +166,7 @@ public class OnlineAccountsManager extends Thread {
         PublicKeyAccount otherAccount = new PublicKeyAccount(repository, onlineAccountData.getPublicKey());
 
         // Check timestamp is 'recent' here
-        if (Math.abs(onlineAccountData.getTimestamp() - now) > ONLINE_TIMESTAMP_MODULUS * 2) {
+        if (Math.abs(onlineAccountData.getTimestamp() - now) > getOnlineTimestampModulus() * 2) {
             LOGGER.trace(() -> String.format("Rejecting online account %s with out of range timestamp %d", otherAccount.getAddress(), onlineAccountData.getTimestamp()));
             return;
         }
@@ -241,7 +248,8 @@ public class OnlineAccountsManager extends Thread {
             return;
 
         // Expire old entries
-        final long cutoffThreshold = now - LAST_SEEN_EXPIRY_PERIOD;
+        final long lastSeenExpiryPeriod = (getOnlineTimestampModulus() * 2) + (1 * 60 * 1000L);
+        final long cutoffThreshold = now - lastSeenExpiryPeriod;
         synchronized (this.onlineAccounts) {
             Iterator<OnlineAccountData> iterator = this.onlineAccounts.iterator();
             while (iterator.hasNext()) {
@@ -372,7 +380,7 @@ public class OnlineAccountsManager extends Thread {
     }
 
     public static long toOnlineAccountTimestamp(long timestamp) {
-        return (timestamp / ONLINE_TIMESTAMP_MODULUS) * ONLINE_TIMESTAMP_MODULUS;
+        return (timestamp / getOnlineTimestampModulus()) * getOnlineTimestampModulus();
     }
 
     /** Returns list of online accounts with timestamp recent enough to be considered currently online. */

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

@@ -12,7 +12,6 @@ import java.util.function.Supplier;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.qortal.account.Account;
-import org.qortal.controller.Controller;
 import org.qortal.controller.OnlineAccountsManager;
 import org.qortal.controller.tradebot.TradeBot;
 import org.qortal.crosschain.ACCT;
@@ -49,7 +48,7 @@ public class PresenceTransaction extends Transaction {
 		REWARD_SHARE(0) {
 			@Override
 			public long getLifetime() {
-				return OnlineAccountsManager.ONLINE_TIMESTAMP_MODULUS;
+				return OnlineAccountsManager.getOnlineTimestampModulus();
 			}
 		},
 		TRADE_BOT(1) {

src/main/resources/blockchain.json

@@ -19,6 +19,7 @@
 	"founderEffectiveMintingLevel": 10,
 	"onlineAccountSignaturesMinLifetime": 43200000,
 	"onlineAccountSignaturesMaxLifetime": 86400000,
+	"onlineAccountsModulusV2Timestamp": 9999999999999,
 	"rewardsByHeight": [
 		{ "height": 1, "reward": 5.00 },
 		{ "height": 259201, "reward": 4.75 },