The app must be transferred by the old owner to the new one.
I a app is “dead” and there is no chance to contect the developer, you can write Athom support. They can perhaps reach the dev over his account email.
If that’s not possible, you can write a new app (or extend the old from Github if it’s ok for the policy) and add it with a new app ID to the store. Athiom will hide the old one then, if they can’t reach the dev, too.
