Applies To:
  • CitectSCADA 1.00 1.01 1.10 1.11 1.20 2.00 2.01

Between some versions of Citect for Windows, the client and server protocol is modified to provide enhancements. If this modification would cause incompatibility between two different versions of Citect, then Citect will not communicate between these two versions. Under this condition, when a client tries to logon to a server of a incompatible version, it will immediately be logged out and generate the hardware error "Incompatible server version". This will prevent the client from communicating with the server.

This change occured between version 1.11 rev 3 and 1.11 rev 4. Versions 1.11 rev 3 and below will not communicate to versions 1.11 rev 4 and above. For example version 1.11 rev 1 will not communicate to version 1.20 rev 0 or 2.0 rev 0. Version 1.11 rev 4 will communicate to version 1.20 rev 0 and 2.0 rev 0 and greater.

The trend system client and server protocol between version 2.xx and version 3.00 has been modified to accommodate the event trends, therefore only version 3.00 clients will be able to communicate to version 3.00 trend servers.

If you receive this error message, you must upgrade your server to the new Citect version. The simplest way is to shutdown all Citects, upgrade to the new version and restart.

If you have redundant servers, you can upgrade on a running plant by first upgrading one server, then all the clients, and then the other server. This will allow you to upgrade Citect to the new version while still providing control of your plant.