Hello, I am using an Asus Zenfone 12 Ultra (16GB / 512GB) running Android 15, build number ZWW_35.1810.1810.411. I am experiencing an issue where VoLTE/IMS registration does not work on this device with my Vodafone Turkey SIM card. VoLTE and VoWiFi services are enabled on my Vodafone line. When I insert the same SIM card into another phone, IMS shows as Registered and VoLTE/VoWiFi work without any issues. On the Zenfone 12 Ultra, in the *#*#4636#*#* menu, IMS status is empty and VoLTE Provisioned appears greyed out. When I make a call, the phone falls back to 3G and mobile data disconnects. The Vodafone APN settings do not appear or cannot be edited on this device. I have already updated the phone to the latest firmware and performed network resets, but the problem persists. Based on these tests, I believe the Vodafone Turkey IMS/VoLTE profile is missing or incompatible on the Zenfone 12 Ultra firmware. Could you please confirm and provide a solution, such as adding the correct IMS profile or a firmware update that enables VoLTE/VoWiFi support for Vodafone Turkey?
