I believe when you first purchased Start11 back in July 2023, it was version 1. Then, in 2024, you purchased an upgrade to Start11 version 2. Even though it is considered an upgrade, you receive a new license key specifically for Start11 v2.
You still retain the license key for Start11 v1, which you may continue to use on any system that supports version 1. However, if you wish to install and activate Start11 v2, you should use only the newer license key.
I hope this explanation makes things clearer.
Thank you,
Basj,
Stardock Community Assistant