Ich habe im Apple-Forum noch diesen Beitrag gefunden es Betrifft nicht nur Swisscom sondern auch Salt.
diego.petraccaOct 23, 2015 4:05 AM
Re: iOS 9.1 draining battery on 6sin response to Zolpho
Thanks a lot Zolpho, the problem is now back! 🙂
it is definitely due to the wifi calling option (now that I remember I have received also an operator update with the 9.1!).
As soon as i have enabled this option, the cpu started again to work heavily, the phone is now hot and the battery drain fast.
I have Salt 22.1 by the way, not Swisscom.
Disabling again the feature does not help, I have tried the reset with home and power button, but no changes.
Network setting restore does not help, setting restore neater.
So I guess the only thing that works is the complete restore which I am going to do now (thanks again Zolpho:-))
So, don't enable wifi calling!