diff --git a/src/network/network_server.cpp b/src/network/network_server.cpp
--- a/src/network/network_server.cpp
+++ b/src/network/network_server.cpp
@@ -878,7 +878,7 @@ NetworkRecvStatus ServerNetworkGameSocke
 	uint32 newgrf_version = p->Recv_uint32();
 
 	/* Check if the client has revision control enabled */
-	if (!IsNetworkCompatibleVersion(client_revision.c_str()) || _openttd_newgrf_version != newgrf_version) {
+	if (!IsNetworkCompatibleVersion(client_revision) || _openttd_newgrf_version != newgrf_version) {
 		/* Different revisions!! */
 		return this->SendError(NETWORK_ERROR_WRONG_REVISION);
 	}