@Solar Eclipse from what I've seen you would be able to install it but not activate it once it rolls off their 3 year support. In 2020 I did manage to re-download and install TT 2018 and 2019 on a different Mac to refile for an issue, in 25 years of using TT that's the furthest I've ever had to go back to run an old version of TT. It seems the 3 year support window is more aimed at refile window than audits. Best thing to do is to save the full PDF with "all forms and worksheets" for your records when you're done with filing season.
