In the FAQ under the "How to update CMS IntelliCAD Premium (PE & PE Plus) standalone software" topic, there is paragraph in bold stating that one should "Please check if you have a license to run the CMS IntelliCAD update".

How do I do that? I have a license for the "CMS IntelliCAD 12.0 PE Plus Upgrade". Is that for one year from purchase? Currently on Windows 10 running version 11.1 and I would like to upgrade to 12.1.

HELP menu > Check for Updates.
You'll see a notice if an update is available or if you're already running the latest version of CMS IntelliCAD software.