My memory from the last time I asked a dev about this is that it has to do with a concern about data integrity. As far as I understand it, their concern is that it’s less disruptive to stop and restart a running app (and then let it stay running after) than to allow docker to start a stopped app as part of the upgrade process and then immediately stop it again. The idea being that starting and then quickly stopping the app would increase the risk that data might be in an unsafe state as part of a startup process, like if the app was already touching data but hadn’t had time to attach signal listeners yet.