When upgrading from V1.x to V2.x or 3.x, does anything need to be changed in the client program?

Yes, the OPC ProgIDs and the client application names have been changed to the following:

• DDE: OMNISRV ⇒ OSRVDDE
• Suitelink: OMNISRV ⇒ OSRVPOLL
• OPC: DSSI.OmniOPCServer.1 ⇒ SWToolbox.OmniServer