> Maybe some apps require an extremely tight coupling with a server, but we should try our best to release complete software to users that will work as close to forever as possible.
That sounds like a good idea. Unless you’re the vendor, and instead of 1000 support requests for version N, you’re now facing 100 support requests for version N, 100 for N−1, 100 for N−2, …, and 100 for N−9.
You're allowed to have a support matrix. You can refuse to support versions that are too old, but you can also just... let people keep using programs on their own computers.
Besides what others said, realistically, the effort to support N versions is not O(n). I think it's something like O(log n), because code will largely be shared between versions - you're not doing a rewrite every release.
