No, there is no requirement to support the software, at least according to what we've heard here. Simply that you can't remove your current rev from the store - you can't prevent people from downloading it.
That's a bit misleading. You can unpublish the app[0], which hides it in the Play Store and prevents new installs. It just doesn't remove the app from the people who already have the app installed, and I think they'll be able to install it on new phones.
I don't know why the OP is choosing not to unpublish the app.