From c90c3a183e67f1e7e777900e543d0c43f40d1ffd Mon Sep 17 00:00:00 2001
From: CalDescent <caldescent@protonmail.com>
Date: Fri, 18 Feb 2022 14:50:29 +0000
Subject: [PATCH] Block peers below 3.1.0

---
 src/main/java/org/qortal/network/Handshake.java | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/main/java/org/qortal/network/Handshake.java b/src/main/java/org/qortal/network/Handshake.java
index d88654cf..cdcff1d7 100644
--- a/src/main/java/org/qortal/network/Handshake.java
+++ b/src/main/java/org/qortal/network/Handshake.java
@@ -74,6 +74,12 @@ public enum Handshake {
 			peer.setPeersConnectionTimestamp(peersConnectionTimestamp);
 			peer.setPeersVersion(versionString, version);
 
+			// Ensure the peer is running at least the version specified in MIN_PEER_VERSION
+			if (peer.isAtLeastVersion(MIN_PEER_VERSION) == false) {
+				LOGGER.debug(String.format("Ignoring peer %s because it is on an old version (%s)", peer, versionString));
+				return null;
+			}
+
 			if (Settings.getInstance().getAllowConnectionsWithOlderPeerVersions() == false) {
 				// Ensure the peer is running at least the minimum version allowed for connections
 				final String minPeerVersion = Settings.getInstance().getMinPeerVersion();
@@ -258,6 +264,9 @@ 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 int POW_BUFFER_SIZE_PRE_131 = 8 * 1024 * 1024; // bytes
 	private static final int POW_DIFFICULTY_PRE_131 = 8; // leading zero bits
 	// Can always be made harder in the future...