VoLTE is working in preinstalled Cyanogen OS but not in CyanogenMod

Question

I was trying to use VoLTE in my phone but eventually landed up with result:

1. CyanogenOS can run VoLTE based SIM card
2. CyanogenMod can't run them.

Tried 1. Setting LTE Only option in ##4636## 2. Setting APN in Sim Settings 3. Also kept the VoLTE in SIM Slot 1

But nothing worked in CyanogenMod.

Does any one have idea how to use both VoLTE and CyanogenMOD both? Currently my phone's CyanogenOS is allowing me to keep only one at a time :)

But I want to use cyanogenMod as it is marshmallow and nightly build updates are released.

Answer 1

You have to enable the internet option for the 4g sim, which you're using and restart the phone. This will only enable LTE not volte internet.

Answer 2

Because CyanogenMod doesn't come with VoLTE soft function. You have to create your custom mod with this function, which is very difficult to do.