diff --git a/core/src/main/java/com/google/bitcoin/core/Peer.java b/core/src/main/java/com/google/bitcoin/core/Peer.java
index cf332f85..5250df2e 100644
--- a/core/src/main/java/com/google/bitcoin/core/Peer.java
+++ b/core/src/main/java/com/google/bitcoin/core/Peer.java
@@ -89,7 +89,8 @@ public class Peer {
     // It is important to avoid a nasty edge case where we can end up with parallel chain downloads proceeding
     // simultaneously if we were to receive a newly solved block whilst parts of the chain are streaming to us.
     private HashSet<Sha256Hash> pendingBlockDownloads = new HashSet<Sha256Hash>();
-
+    // The lowest version number we're willing to accept. Lower than this will result in an immediate disconnect.
+    private int minProtocolVersion = Pong.MIN_PROTOCOL_VERSION;
     // When an API user explicitly requests a block or transaction from a peer, the InventoryItem is put here
     // whilst waiting for the response. Synchronized on itself. Is not used for downloads Peer generates itself.
     private static class GetDataRequest {
@@ -279,6 +280,11 @@ public class Peer {
                         listener.onPeerConnected(Peer.this);
                     }
                 });
+                if (peerVersionMessage.clientVersion < minProtocolVersion) {
+                    log.warn("Connected to a peer speaking protocol version {} but need {}, closing",
+                            peerVersionMessage.clientVersion, minProtocolVersion);
+                    e.getChannel().close();
+                }
             } else if (m instanceof VersionAck) {
                 synchronized (Peer.this) {
                     if (peerVersionMessage == null) {
@@ -295,7 +301,6 @@ public class Peer {
             } else if (m instanceof Pong) {
                 processPong((Pong)m);
             } else {
-                // TODO: Handle the other messages we can receive.
                 log.warn("Received unhandled message: {}", m);
             }
         }
@@ -1203,4 +1208,21 @@ public class Peer {
     public synchronized long getBestHeight() {
       return peerVersionMessage.bestHeight + blocksAnnounced;
     }
+
+    /**
+     * The minimum P2P protocol version that is accepted. If the peer speaks a protocol version lower than this, it
+     * will be disconnected.
+     * @return if not-null then this is the future for the Peer disconnection event.
+     */
+    public ChannelFuture setMinProtocolVersion(int minProtocolVersion) {
+        synchronized (this) {
+            this.minProtocolVersion = minProtocolVersion;
+        }
+        if (getVersionMessage().clientVersion < minProtocolVersion) {
+            log.warn("{}: Disconnecting due to new min protocol version {}", this, minProtocolVersion);
+            return Channels.close(channel);
+        } else {
+            return null;
+        }
+    }
 }
diff --git a/core/src/test/java/com/google/bitcoin/core/PeerTest.java b/core/src/test/java/com/google/bitcoin/core/PeerTest.java
index 122c4c48..18debab1 100644
--- a/core/src/test/java/com/google/bitcoin/core/PeerTest.java
+++ b/core/src/test/java/com/google/bitcoin/core/PeerTest.java
@@ -630,8 +630,7 @@ public class PeerTest extends TestWithNetworkConnections {
         t2.setLockTime(999999);
         // Add a fake input to t3 that goes nowhere.
         Sha256Hash t3 = Sha256Hash.create("abc".getBytes(Charset.forName("UTF-8")));
-        t2.addInput(new TransactionInput(unitTestParams, t2, new byte[]{}, new TransactionOutPoint(unitTestParams, 0,
-                t3)));
+        t2.addInput(new TransactionInput(unitTestParams, t2, new byte[]{}, new TransactionOutPoint(unitTestParams, 0, t3)));
         t2.addOutput(Utils.toNanoCoins(1, 0), new ECKey());
         Transaction t1 = new Transaction(unitTestParams);
         t1.addInput(t2.getOutput(0));
@@ -664,6 +663,33 @@ public class PeerTest extends TestWithNetworkConnections {
             assertNull(vtx[0]);
     }
 
+    @Test
+    public void disconnectOldVersions1() throws Exception {
+        expect(channel.close()).andReturn(null);
+        control.replay();
+        // Set up the connection with an old version.
+        handler.connectRequested(ctx, new UpstreamChannelStateEvent(channel, ChannelState.CONNECTED, socketAddress));
+        VersionMessage peerVersion = new VersionMessage(unitTestParams, OTHER_PEER_CHAIN_HEIGHT);
+        peerVersion.clientVersion = 500;
+        DownstreamMessageEvent versionEvent =
+                new DownstreamMessageEvent(channel, Channels.future(channel), peerVersion, null);
+        handler.messageReceived(ctx, versionEvent);
+    }
+
+    @Test
+    public void disconnectOldVersions2() throws Exception {
+        expect(channel.close()).andReturn(null);
+        control.replay();
+        // Set up the connection with an old version.
+        handler.connectRequested(ctx, new UpstreamChannelStateEvent(channel, ChannelState.CONNECTED, socketAddress));
+        VersionMessage peerVersion = new VersionMessage(unitTestParams, OTHER_PEER_CHAIN_HEIGHT);
+        peerVersion.clientVersion = 70000;
+        DownstreamMessageEvent versionEvent =
+                new DownstreamMessageEvent(channel, Channels.future(channel), peerVersion, null);
+        handler.messageReceived(ctx, versionEvent);
+        peer.setMinProtocolVersion(500);
+    }
+
     // TODO: Use generics here to avoid unnecessary casting.
     private Message outbound() {
         List<DownstreamMessageEvent> messages = event.getValues();