The accepted answer is a workaround that shouldn't be needed, if the bug is fixed in the first place. @yasmin777 any update on your bug report?

We're having a VoIP App that is potentially connected to a VoIP server in a different country (over VPN). We use the CTCarrier mobileCountryCode to route emergency calls based on the users location to the system and not the remote VoIP server (in that other country, where that emergency number might have a totally different meaning). This change can hurt people. (still investigating how this deprecation got unnoticed on our side)