The activation key will be carried over when upgrading, but as in any upgrade procedure backup your activation key and 2.3 config as a precaution measure
Only when downgrading is where you have to pay attention from 3.2 to 2.3 activation key may be reseted based on the feature sets.
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: