Hello, I used to use Illustrator CC 2018 on my work computer. It was having trouble opening AI and PDF files. I uninstalled the program and now I can't even install it back on the computer due to the program no longer being supported for download. 2018 was only 2 years ago. This is a huge problem for your users. Maybe have some kind of warning or do the right thing and offer support for programs older than 2 years.