Amazon came with sad news
Today we are announcing that starting on September 20, 2017, we are discontinuing the GameCircle Social Features, which will remove the customer’s ability to maintain a list of GameCircle Friends. Additionally, certain GameCircle Friends features will be less visible to customers outside of the game play experience: customers will no longer see GameCircle achievements, Friend leaderboards, and other information from their Home screen or Games gateway experience on Fire Tablets. The in-game experience for GameCircle will remain mostly unchanged, and no action is required on your part. However, if you have integrated the Social Service SDK methods - getFriendIds(), requestLocalPlayer(), and getBatchFriends(), starting from December 1, 2017, these methods will no longer return data. Games that use these methods can continue to call them, but data will not be flowing.
Part of API won't be longer available -> an official information.
Amazon is discontinuing the social features of GameCircle -> an official information.