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Hello I'm reading a lot about people talking about "sandbox" accounts (that from my understanding actually is no longer available starting from iOS9) or development builds... but I can't find a comprehensive documentation that explain what to do to test achievements. This is the flow that I'm following to add achievements to my game. It is not fully working since I can't see the popup "completed" when I set the achievement as accomplished but other items are working as expected (I can set an achievement as done and I can retrieve the list of completed achievements). Description of my current situation Added all the achievements via AppStoreConnect Created a new version of my App and added the Achievements to this new version (This version has not been submitted yet, but the App is already on the App Store with another version) via AppStoreConnect My App is written in Unity. So I've added all the needed code there. I see that I can unlock achievements and I can retrieve a list of all the unlocked achievements. So the code seems to work as expected. I'm running the App directly from Xcode... it is not uploaded to Testflight. Problems and Doubts When I unlock an achievement the "completed" popup is not shown If I open GameCenter, under my game, I do not see a list of available Achievements. I suppose this is the correct behaviour since the version with the achievements has not been submitted and approved. I'm wondering... which is the right way to test achievements? Someone is talking about using "development" builds... other say to use sandbox accounts... is there a documentation out there that explains the right flow?!