Hey,
I have an existing iOS App with Game Center Leaderboards and Achievements that I now want to transfer to a Game Center Group for multi-platform shared leaderboards. (OS X / tvOS)
1. I have an update already in the review pipeline set to the standard leaderboard id's.
2. I have setup a Game Center Group for this App post this being in review.
3. I want to retain all player scores / achievements
Notes: According to Diego:
"I migrated to my game to GC groups, then submitted my game for OS X using the grp prefix. I didn't have to make any changes to the iOS version, it just worked. Game is called Arcane Tower in case you're interested"
I checked his App on iOS and OS X and the leaderboards are in sync.
So it seems the old id's (original ones) seem to keep in sync with the new grp versions. However if you create a new application using these you must use the grp prefix to address them (say the OS X version or tvOS).
My questions are:
1. Do I need to modify the iOS leaderboard / achievement id's to include the grp* prefix?
2. Do I need to update this due to submitting an update?
3. Will player scores / achievements be retained (very important).
4. Are there any best approaches to this situation?