Hello.
As a foreword, we do not officially support old versions. But we still try to.

The license is stored in the registry. If you have moved the whole VM or its system disk, the license will stay. It is not technically protected against change of the VM or its virtual hardware etc.

I see no reason to think why there even is a problem with the license. You need to describe the actual symptoms of the problem, that is, what do you mean by "the opc server don't work as expected".

How have you come to the suspicion that something is wrong with the license - given that there are millions of other possible causes?

It is also weird how you formulate the problem - "... are some problem with opc server." - because our software is an OPC client, not an OPC server. If they/you believe there is a problem with the OPC server, you should primarily look at the server. And that's not QuickOPC.

Best regards