Those who use T-Mobile in their latest smartphones will appreciate T-Mobile’s Wi-Fi Calling facility, which helps you out in areas where cellular network cannot penetrate easily. The availability of such facility will keep the users away from custom ROMs, even if they use multi-carrier devices. However, if you are a CyanogenMod user, the problem is going to get solved for you.
Roman Birg, former AOKP ROM team leader and current Cyanogen Inc. employee, has posted the above shown screenshot to Google+. As you can see in the image, the T-Mobile Wi-Fi Calling feature can be clearly seen on a software build that has the AOSP style in it. In the comments for the screenshot, Birg has confirmed that the software indeed is CyanogenMod 13 and is based on the latest Android 6.0 Marshmallow. As reported by AndroidPolice, the latest CyanogenMod 13 implements the Wi-Fi calling feature by using a mix of Wi-Fi calling code included in the AOSP already along with some special code that the Cyanogen team cannot reveal.
Smartphone users and manufacturers in the US are opening their arms to off-contract devices, which makes Wi-Fi calling an essential feature for stock devices as well as ROMs. We don’t know when the CyanogenMod 13 will come out, but the alpha and beta builds are expected in the upcoming months.