Only subscriptions that make sense to me a cloud based ones that can’t function at all without access to the internet due to not being able to retrieve content needed to function. Examples that come to mind are netflix and spotify, since even though you can download content to watch or hear offline you need internet to retrieve new content. Means there are hosting costs, and I’m basically paying to not host all that content myself.
But, anything else doesn’t make sense to me. If app wants to charge again then they can do another version release, and let people keep using the old version if they want while stopping updates for it. I don’t do subscriptions.