for users with e.g. older operating systems or using plugins incompatible with the latest SU version, the license data should be compatible with at least the previous version and at least the same system… in the boundaries of the license agreement of course.
Sketchup Pro for Mac OS 10.9.5
The serial number i purchased for pro 2017 won't work on my pro 2014 (only version for Vista)
Wanting to buy SU PRO
Purchased Wrong License
If I purchased a 2017 PRO license, can I have a previous PRO version for free?
or better, make license data unique sothat even every further version can be run with an existing and valid license which is known and provided by the Trimble SketchUp license server anyhow.
This would allow to get rid the need for providing new license data (in a timely manner and via the resellers) to customers w/ running maintenance as well as the problems which existing customers may realize when the previous version expires 60 days after the activation of the new version.