diff --git a/src/network/network_func.h b/src/network/network_func.h
--- a/src/network/network_func.h
+++ b/src/network/network_func.h
@@ -78,6 +78,7 @@ bool NetworkServerChangeClientName(Clien
 void NetworkServerDoMove(ClientID client_id, CompanyID company_id);
 void NetworkServerSendRcon(ClientID client_id, TextColour colour_code, const std::string &string);
 void NetworkServerSendChat(NetworkAction action, DestType type, int dest, const std::string &msg, ClientID from_id, int64 data = 0, bool from_admin = false);
+void NetworkServerSendExternalChat(const std::string &source, TextColour colour, const std::string &user, const std::string &msg);
 
 void NetworkServerKickClient(ClientID client_id, const std::string &reason);
 uint NetworkServerKickOrBanIP(ClientID client_id, bool ban, const std::string &reason);