I have seen applications that check the version on launch, inform the user about an update being available and in some cases also prevent the app from running f

I have seen applications that check the version on launch, inform the user about an update being available and in some cases also prevent the app from running further if it's not updated. Technically this is just a matter of writing the application this way. Even though users may be inconvenienced and annoyed, if the application and its service have not been terrible and if you follow a proper "deprecate and then eliminate" process, most users wouldn't mind updating on a prompt that comes at launch time. More so if the "what's new", along with a "why update" is described on launch. Nothing stops a developer of a client-server application from developing this way.