A Boolean value that states whether this achievement can be earned multiple times.
- iOS 6.0+
- macOS 10.8+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
If the value of this property is
false, then the achievement may only be earned once. After the achievement is earned, Game Center ignores any further progress submitted for it. If the value of this property is
true, then the achievement is considered earned each time your game reports progress to Game Center that completes the achievement. This means that any appropriate banners are displayed to the player again, challenges based on the achievement are completed, and so on.