diff --git a/dlls/rpcrt4/rpc_binding.c b/dlls/rpcrt4/rpc_binding.c
index 1972e4f3591..035c36e026a 100644
--- a/dlls/rpcrt4/rpc_binding.c
+++ b/dlls/rpcrt4/rpc_binding.c
@@ -865,21 +865,13 @@ RPC_STATUS WINAPI RpcBindingToStringBindingW( RPC_BINDING_HANDLE Binding, LPWSTR
  *  Exists in win9x and winNT, but with different number of arguments
  *  (9x version has 3 arguments, NT has 2).
  */
-#ifdef WINNT
 RPC_STATUS WINAPI I_RpcBindingSetAsync( RPC_BINDING_HANDLE Binding, RPC_BLOCKING_FN BlockingFn)
-#else
-RPC_STATUS WINAPI I_RpcBindingSetAsync( RPC_BINDING_HANDLE Binding, RPC_BLOCKING_FN BlockingFn, unsigned long ServerTid )
-#endif
 {
   RpcBinding* bind = (RpcBinding*)Binding;
 
-  TRACE( "(%p,%p,%ld): stub\n", Binding, BlockingFn, ServerTid );
+  TRACE( "(%p,%p): stub\n", Binding, BlockingFn );
 
   bind->BlockingFn = BlockingFn;
 
-  #ifndef WINNT
-  bind->ServerTid = ServerTid;
-  #endif
-
   return RPC_S_OK;
 }
diff --git a/dlls/rpcrt4/rpc_server.c b/dlls/rpcrt4/rpc_server.c
index d3b4a698407..e91305cb280 100644
--- a/dlls/rpcrt4/rpc_server.c
+++ b/dlls/rpcrt4/rpc_server.c
@@ -690,7 +690,7 @@ RPC_STATUS WINAPI I_RpcServerStopListening( void )
 /***********************************************************************
  *             I_RpcWindowProc (RPCRT4.@)
  */
-UINT WINAPI I_RpcWindowProc( void* hWnd, UINT Message, UINT wParam, ULONG lParam )
+LONG WINAPI I_RpcWindowProc( HWND hWnd, UINT Message, WPARAM wParam, LPARAM lParam )
 {
   FIXME( "(%p,%08x,%08x,%08lx): stub\n", hWnd, Message, wParam, lParam );
 
diff --git a/include/rpcdcep.h b/include/rpcdcep.h
index 91714079ea8..8a319f9cb09 100644
--- a/include/rpcdcep.h
+++ b/include/rpcdcep.h
@@ -93,11 +93,7 @@ typedef struct _RPC_CLIENT_INTERFACE
 #define TRANSPORT_TYPE_LPC  0x04
 #define TRANSPORT_TYPE_WMSG 0x08
 
-#ifdef WINNT
 typedef RPC_STATUS (*RPC_BLOCKING_FN)(void* hWnd, void* Context, HANDLE hSyncEvent);
-#else
-typedef RPC_STATUS (*RPC_BLOCKING_FN)(void* hWnd, void* Context, void* hSyncEvent);
-#endif
 
 RPCRTAPI RPC_STATUS RPC_ENTRY
   I_RpcGetBuffer( RPC_MESSAGE* Message );
@@ -130,25 +126,15 @@ RPCRTAPI RPC_STATUS RPC_ENTRY
 RPCRTAPI RPC_STATUS RPC_ENTRY
   I_RpcAsyncSendReceive( RPC_MESSAGE* Message, void* Context, HWND hWnd );
 
-#ifdef WINNT
 RPCRTAPI RPC_STATUS RPC_ENTRY
   I_RpcBindingSetAsync( RPC_BINDING_HANDLE Binding, RPC_BLOCKING_FN BlockingFn );
-#else
-RPCRTAPI RPC_STATUS RPC_ENTRY
-  I_RpcBindingSetAsync( RPC_BINDING_HANDLE Binding, RPC_BLOCKING_FN BlockingFn, unsigned long ServerTid );
-#endif
 
 /* WIN9x */
 RPCRTAPI RPC_STATUS RPC_ENTRY
   I_RpcSetThreadParams( int fClientFree, void* Context, void* hWndClient );
 
-#ifdef WINNT
 RPCRTAPI LONG RPC_ENTRY
   I_RpcWindowProc( HWND hWnd, UINT Message, WPARAM wParam, LPARAM lParam );
-#else
-RPCRTAPI unsigned int RPC_ENTRY
-  I_RpcWindowProc( void* hWnd, unsigned int Message, unsigned int wParam, unsigned long lParam );
-#endif
 
 /* WINNT */
 RPCRTAPI RPC_STATUS RPC_ENTRY