I've had some C3 games on my apple devices for very long time. Iphone 11 and Ipad air2.
Now when I got, and installed, the ios 15 (and ios 15.0.1) then I experienced severe issues on my games.
Note that this is for the already installed games, which was exported very long time ago.
First when I opened the game I experienced very long loading time when opened, then all audio was gone in the game.
Next time I started the game was the same, but now also all graphics was changed into black squares. So all grapchics was currupt, and all audio was gone.
Now after some hard reboots of the device I get the game up and running, but when I show an ad, the game audio continue to play in the background, making the sound to be totally off. For me this indicates that the game activity continues to run even when a Admob-activity is shown above (its an interstitial), this should not happen, the game (and audio) should be paused during this. Thats how it worked below ios 15.
I've discussed this with some other C3 developers the past days and also some other experience some really odd issues.
Please feel free to describe if you experience any issues.
I guess this is some weird bugs with webkit or something(?)