diff --git a/ethereumj-core/src/main/java/org/ethereum/config/SystemProperties.java b/ethereumj-core/src/main/java/org/ethereum/config/SystemProperties.java
index 590e71aa..68a2f843 100644
--- a/ethereumj-core/src/main/java/org/ethereum/config/SystemProperties.java
+++ b/ethereumj-core/src/main/java/org/ethereum/config/SystemProperties.java
@@ -21,7 +21,7 @@ public class SystemProperties {
 	private static Logger logger = LoggerFactory.getLogger(SystemProperties.class);
 
 	private static int      DEFAULT_TX_APPROVE_TIMEOUT = 10;
-	private static int      DEFAULT_PROTOCOL_VERSION = 33;
+	private static byte      DEFAULT_PROTOCOL_VERSION = 33;
 	private static String   DEFAULT_DISCOVERY_PEER_LIST = "poc-6.ethdev.com:30303";
 	private static String   DEFAULT_ACTIVE_PEER_IP = "poc-6.ethdev.com";
 	private static int      DEFAULT_ACTIVE_PORT = 30303;
@@ -82,9 +82,9 @@ public class SystemProperties {
 		}
 	}
 
-	public int protocolVersion() {
+	public byte protocolVersion() {
 		if (prop.isEmpty()) return DEFAULT_PROTOCOL_VERSION;
-		return Integer.parseInt(prop.getProperty("protocol.version"));
+		return Byte.parseByte(prop.getProperty("protocol.version"));
 	}
 
 	public boolean peerDiscovery() {
diff --git a/ethereumj-core/src/test/java/org/ethereum/net/PeersMessageTest.java b/ethereumj-core/src/test/java/org/ethereum/net/PeersMessageTest.java
index 0fa4dacb..f1be40fa 100644
--- a/ethereumj-core/src/test/java/org/ethereum/net/PeersMessageTest.java
+++ b/ethereumj-core/src/test/java/org/ethereum/net/PeersMessageTest.java
@@ -8,10 +8,10 @@ import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Set;
 
-import org.ethereum.net.client.Peer;
 import org.ethereum.net.message.Command;
 import org.ethereum.net.message.GetPeersMessage;
 import org.ethereum.net.message.PeersMessage;
+import org.ethereum.net.peerdiscovery.PeerData;
 import org.junit.Test;
 import org.spongycastle.util.encoders.Hex;
 
@@ -51,8 +51,8 @@ public class PeersMessageTest {
 
         assertEquals(2, peersMessage.getPeers().size());
 
-        Iterator<Peer> it = peersMessage.getPeers().iterator(); it.next();
-        Peer peer = it.next();
+        Iterator<PeerData> it = peersMessage.getPeers().iterator(); it.next();
+        PeerData peer = it.next();
 
         assertEquals(Command.PEERS, peersMessage.getCommand());
         assertEquals("/81.99.225.18", peer.getAddress().toString());
@@ -63,9 +63,9 @@ public class PeersMessageTest {
 
     @Test /*  PeersMessage 2 from constructor */
     public void testPeers_2() throws UnknownHostException {
-    	Set<Peer> peers = new HashSet<>();
-    	peers.add(new Peer(InetAddress.getByName("82.217.72.169"), 30303, "585764a3c49a3838c69ad0855abfeb5672f71b072af62082b5679961781100814b8de88a8fbc1da7c73791f88159d73b5d2a13a5579535d603e045c3db5cbb75"));
-    	peers.add(new Peer(InetAddress.getByName("192.168.1.193"), 30303, ""));
+    	Set<PeerData> peers = new HashSet<>();
+    	peers.add(new PeerData(InetAddress.getByName("82.217.72.169"), 30303, "585764a3c49a3838c69ad0855abfeb5672f71b072af62082b5679961781100814b8de88a8fbc1da7c73791f88159d73b5d2a13a5579535d603e045c3db5cbb75"));
+    	peers.add(new PeerData(InetAddress.getByName("192.168.1.193"), 30303, ""));
         PeersMessage peersMessage = new PeersMessage(peers);
         System.out.println(peersMessage.toString());