Introduction

As part of the release of iOS 9 and El Capitan, the Game Center development sandbox has been eliminated, allowing all pre-release development to occur in exactly the same server environment as released games. This change brings several advantages including:

• Simplifying update testing by allowing testers to play with the full player base, not just other testers

• Removing any implementation differences between the sandbox and release environments

For most developers, this change has no effect on the development process, however, there are a few side effects of this change you should be aware of.

Existing Sandbox Accounts

No existing sandbox data is being preserved during this transition. As part of this change you will lose all of your data that currently resides in the sandbox environment. This includes:

• Profile data, including nickname and profile image

• Leaderboard scores

• Achievements

• Challenges

• Turn Based Game sessions

• Friends list

If the Apple ID used in the sandbox has not previously been used in the production environment, you will be prompted to create a new profile after the transition has occurred.

Achievements and Leaderboards

By design the Achievements and High Scores of a particular Game Center user have always been visible to that user's friends. As part of this change, that will include Achievements and Leaderboard Scores that have not been formally released as part of a particular game version. Similarly, any game a Game Center player has played is visible to all of that players friends, even if that game has not yet been released.

If any of this data needs to be kept secret as part of your overall release strategy, then you will need to create separate accounts for pre-release testing and carefully manage which Game Center users are allowed to become friends with those accounts.

For more information on this issue, see the WWDC 2015 Session: Going Social with ReplayKit and Game Center.

Multiplayer Compatibility

For both turn based and realtime multiplayer games, the iTunes Connect multiplayer compatibility matrix only applies to versions approved and released to the App Store. Prerelease versions will connect with all other versions of the app, even if the compatibility matrix would have otherwise precluded it. In the worst case, this can potentially lead to crashes and data corruption in earlier versions of your app. Care should be taken when developing and testing new versions of your multiplayer communication format.

Server Side Authentication

After this change generateIdentityVerificationSignatureWithCompletionHandler will continue to work correctly and simply return the publicKeyUrl for the App Store servers instead of the sandbox. However, if your server had cached the publicKeyUrl and expected a particular environment to sign with a particular key, your server will need to be updated to match the new behavior.