Dear Swisscom
Can you explain to me why you don’t allow the setting between Mobile Preferred and WiFi Preferred on Android phones that are active with WiFi calling?
If you search the net, it seems to be a flag that the provider can specify.
Tested it myself with a Yallo and Salt SIM on a Huawei P30 Pro and S9+.
After changing the SIM and resetting the APN settings, these providers give you another option below Enable/Disable WiFi calling whether you prefer the mobile network or WiFi.
As soon as you insert your SIM, the option disappears after provisioning and mobile is definitely preferred in the background.
The phones only switch to WiFi calling mode if there is a virtual loss of signal or forced airplane mode but WiFi is activated.
In our case, for example, this is externally annoying because we have minimal Edge/3G reception at home (and therefore no VoLTE) but the devices stubbornly prefer the mobile network due to their presets and often lose the signal completely. A clean handover to VoWiFi is not possible due to the lack of VoLTE.
Hence the request to give customers the choice 🙂
By the way, with a Oneplus 7 Pro and a few workarounds, VoLTE and VoWifi work for me and the option with preferred remains 🙂
This is just a side note, but it would be really helpful if this were possible in the normal way on devices that are fully provisioned.