diff --git a/OpenRA.Server/Server.cs b/OpenRA.Server/Server.cs
index c29924d4bb..3098e651e5 100644
--- a/OpenRA.Server/Server.cs
+++ b/OpenRA.Server/Server.cs
@@ -77,7 +77,8 @@ namespace OpenRA.Server
 
 				// assign the player number.
 				newConn.PlayerIndex = ChooseFreePlayerIndex();
-				newConn.socket.Send( BitConverter.GetBytes( newConn.PlayerIndex ) );
+				newConn.socket.Send(BitConverter.GetBytes(ProtocolVersion.Version));
+				newConn.socket.Send(BitConverter.GetBytes(newConn.PlayerIndex));
 				conns.Add(newConn);
 
 				lobbyInfo.Clients.Add(
@@ -90,9 +91,6 @@ namespace OpenRA.Server
 						State = Session.ClientState.NotReady
 					});
 
-				DispatchOrdersToClient(newConn, 0, 0,
-					new ServerOrder(newConn.PlayerIndex, "AssignPlayer", "").Serialize());
-
 				Console.WriteLine("Accepted connection from {0}.",
 					newConn.socket.RemoteEndPoint);
 
diff --git a/OpenRa.FileFormats/OpenRa.FileFormats.csproj b/OpenRa.FileFormats/OpenRa.FileFormats.csproj
index 8e12639d1b..617103e8ae 100644
--- a/OpenRa.FileFormats/OpenRa.FileFormats.csproj
+++ b/OpenRa.FileFormats/OpenRa.FileFormats.csproj
@@ -72,6 +72,7 @@
     <Compile Include="Palette.cs" />
     <Compile Include="PlayerColorRemap.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="ProtocolVersion.cs" />
     <Compile Include="Session.cs" />
     <Compile Include="ShpReader.cs" />
     <Compile Include="ShroudPaletteRemap.cs" />
diff --git a/OpenRa.FileFormats/ProtocolVersion.cs b/OpenRa.FileFormats/ProtocolVersion.cs
new file mode 100644
index 0000000000..8d0eef523c
--- /dev/null
+++ b/OpenRa.FileFormats/ProtocolVersion.cs
@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace OpenRa.FileFormats
+{
+	public static class ProtocolVersion
+	{
+		// you *must* increment this whenever you make an incompatible protocol change
+		public static readonly int Version = 1;
+	}
+}
diff --git a/OpenRa.Game/Game.cs b/OpenRa.Game/Game.cs
index 3331e5d171..f1a55533ec 100644
--- a/OpenRa.Game/Game.cs
+++ b/OpenRa.Game/Game.cs
@@ -87,7 +87,6 @@ namespace OpenRa
 
 		internal static void Initialize(string mapName, Renderer renderer, int2 clientSize, int localPlayer, Controller controller)
 		{
-			//localPlayerIndex = localPlayer;
 			Game.renderer = renderer;
 			Game.clientSize = clientSize;
 
@@ -102,7 +101,6 @@ namespace OpenRa
 			ChangeMap(mapName);
 
 			if (Settings.Replay != "")
-				//orderManager = new OrderManager(new IOrderSource[] { new ReplayOrderSource(Settings.Replay) });
 				throw new NotImplementedException();
 			else
 			{
@@ -197,6 +195,9 @@ namespace OpenRa
 
 			LobbyInfo = session;
 
+			if (Game.orderManager.Connection.ConnectionState == ConnectionState.Connected)
+				world.SetLocalPlayer(Game.orderManager.Connection.LocalClientId);
+
 			if (Game.orderManager.FramesAhead != LobbyInfo.GlobalSettings.OrderLatency
 				&& !Game.orderManager.GameStarted)
 			{
@@ -277,14 +278,6 @@ namespace OpenRa
 					new Order( "ToggleReady", Game.world.LocalPlayer.PlayerActor, "" ) { IsImmediate = true } );
 			}
 
-			/* temporary hack: DO NOT LEAVE IN */
-			if( e.KeyCode == Keys.F2 )
-				Game.world.LocalPlayer = Game.world.players[ ( Game.world.LocalPlayer.Index + 1 ) % 4 ];
-			if( e.KeyCode == Keys.F3 )
-				Game.controller.orderGenerator = new SellOrderGenerator();
-			if( e.KeyCode == Keys.F4 )
-				Game.controller.orderGenerator = new RepairOrderGenerator();
-
 			if( !Game.chat.isChatting )
 				if( e.KeyCode >= Keys.D0 && e.KeyCode <= Keys.D9 )
 					Game.controller.DoControlGroup( world, (int)e.KeyCode - (int)Keys.D0, (Modifiers)(int)e.Modifiers );
diff --git a/OpenRa.Game/Network/Connection.cs b/OpenRa.Game/Network/Connection.cs
index 5becdcee8a..ee5b26cd2b 100755
--- a/OpenRa.Game/Network/Connection.cs
+++ b/OpenRa.Game/Network/Connection.cs
@@ -5,6 +5,7 @@ using System.Text;
 using System.Net.Sockets;
 using System.Threading;
 using System.IO;
+using OpenRa.FileFormats;
 
 namespace OpenRa.Network
 {
@@ -78,6 +79,13 @@ namespace OpenRa.Network
 				{
 					socket = new TcpClient( host, port );
 					var reader = new BinaryReader( socket.GetStream() );
+					var serverProtocol = reader.ReadInt32();
+
+					if (ProtocolVersion.Version != serverProtocol)
+						throw new InvalidOperationException(
+							"Protocol version mismatch. Server={0} Client={1}"
+								.F(serverProtocol, ProtocolVersion.Version));
+
 					clientId = reader.ReadInt32();
 					connectionState = ConnectionState.Connected;
 
diff --git a/OpenRa.Game/Network/UnitOrders.cs b/OpenRa.Game/Network/UnitOrders.cs
index c43d62356b..b5fade9941 100755
--- a/OpenRa.Game/Network/UnitOrders.cs
+++ b/OpenRa.Game/Network/UnitOrders.cs
@@ -18,12 +18,6 @@ namespace OpenRa.Network
 						Game.chat.AddLine(order.Player, order.TargetString);
 					break;
 				}
-			case "AssignPlayer":
-				{
-					order.Player.World.LocalPlayer = order.Player;
-					Game.chat.AddLine(order.Player, "is now YOU.");
-					break;
-				}
 			case "StartGame":
 				{
 					Game.chat.AddLine(Color.White, "Server", "The game has started.");
diff --git a/OpenRa.Game/World.cs b/OpenRa.Game/World.cs
index 6edf470c32..43e2d4c670 100644
--- a/OpenRa.Game/World.cs
+++ b/OpenRa.Game/World.cs
@@ -21,10 +21,15 @@ namespace OpenRa
 		public Player LocalPlayer
 		{
 			get { return players[localPlayerIndex]; }
-			set
+		}
+
+		public void SetLocalPlayer(int index)
+		{
+			if (index != localPlayerIndex)
 			{
-				localPlayerIndex = value.Index;
-				Game.viewport.GoToStartLocation( value );
+				localPlayerIndex = index;
+				Game.viewport.GoToStartLocation(LocalPlayer);
+				Game.chat.AddLine(LocalPlayer, "is now YOU");
 			}
 		}