Updating legacy subscriptions
If your subscriptions have been around for a while, Google Play Console may consider them “legacy” subscriptions and make them read-only. These will continue to work using their deprecated InAppProducts API.
However, if you want to make a change to one of these subscriptions they will ask you if you want to make them editable, and warn you that the change could break existing integrations using the InAppProducts API. The good news is that we have integrated the Subscription Publishing API, so this change will not break the subscriptions functionality in the apps.
You are therefore free to “make subscription editable”.