Depends on what the OP is doing. Some people just have repeated tasks of preparing documents. I don't see any security implications of using 7-year-old software

Depends on what the OP is doing. Some people just have repeated tasks of preparing documents. I don't see any security implications of using 7-year-old software as long as the user is just using it for authoring some PDFs and not opening anything of an external origin. The OS, if connected to the Internet, must be up to date though. That being said I agree that licensing/subscription model makes sense even though I personally hate it too.