diff --git a/Client/Client.csproj b/Client/Client.csproj
index f851aa4d..8d9b31d9 100644
--- a/Client/Client.csproj
+++ b/Client/Client.csproj
@@ -310,7 +310,8 @@
   <ItemGroup />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <PropertyGroup>
-    <PostBuildEvent>copy "$(TargetPath)" "$(TargetDir)client.bin" /Y</PostBuildEvent>
+    <PostBuildEvent Condition="'$(OS)' == 'Windows_NT' ">copy "$(TargetPath)" "$(TargetDir)client.bin" /Y</PostBuildEvent>
+    <PostBuildEvent Condition="'$(OS)' != 'Windows_NT' ">cp "$(TargetPath)" "$(TargetDir)client.bin"</PostBuildEvent>
   </PropertyGroup>
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
diff --git a/Server/Core/Networking/Server.cs b/Server/Core/Networking/Server.cs
index 749039c2..f5e71f89 100644
--- a/Server/Core/Networking/Server.cs
+++ b/Server/Core/Networking/Server.cs
@@ -256,7 +256,9 @@ public void Listen(ushort port, bool ipv6)
                     if (Socket.OSSupportsIPv6 && ipv6)
                     {
                         _handle = new Socket(AddressFamily.InterNetworkV6, SocketType.Stream, ProtocolType.Tcp);
-                        _handle.SetSocketOption(SocketOptionLevel.IPv6, SocketOptionName.IPv6Only, false);
+                        // fix for mono compatibility, SocketOptionName.IPv6Only
+                        SocketOptionName ipv6only = (SocketOptionName)27;
+                        _handle.SetSocketOption(SocketOptionLevel.IPv6, ipv6only, 0);
                         _handle.Bind(new IPEndPoint(IPAddress.IPv6Any, port));
                     }
                     else
diff --git a/Server/Core/Networking/Utilities/UPnP.cs b/Server/Core/Networking/Utilities/UPnP.cs
index e6b194f7..e9bc4ee9 100644
--- a/Server/Core/Networking/Utilities/UPnP.cs
+++ b/Server/Core/Networking/Utilities/UPnP.cs
@@ -70,7 +70,7 @@ public static bool CreatePortMap(int port, out int externalPort)
                 Mapping mapping = new Mapping(Protocol.Tcp, port, port);
 
                 for (int i = 0; i < 3; i++)
-                    _device.CreatePortMap(mapping);
+                    _device.CreatePortMapAsync(mapping);
 
                 if (_mappings.ContainsKey(mapping.PrivatePort))
                     _mappings[mapping.PrivatePort] = mapping;
@@ -102,7 +102,7 @@ public static void DeletePortMap(int port)
                 try
                 {
                     for (int i = 0; i < 3; i++)
-                        _device.DeletePortMap(mapping);
+                        _device.DeletePortMapAsync(mapping);
                 }
                 catch (MappingException)
                 {
diff --git a/Server/lib/Mono.Nat.dll b/Server/lib/Mono.Nat.dll
index 66416745..b477b714 100644
Binary files a/Server/lib/Mono.Nat.dll and b/Server/lib/Mono.Nat.dll differ