I purchased TT 2019 in 2019. Software support has always meant to me that the developer will not support the application if there are changes to the underlying OS. I recognized that as a possibility. As a result I loaded 2019 on a Mac mini with 10.15.7. This was prior to the Oct 2023 deadline you mention. If you purchase software and you have a license for it, then as long as the system it is running on does not change the application should not stop working. This would be no different than purchasing a car and when the 5 year , 50K mile warranty ends the car simply turns itself off
