2024 March 19 Update: I recommend to use this guide as it's working without root accessA lot of things changed with OnePlus brand, now they are exactly same as Oppo (OxygenOS 13 and ColorOS 13 are exactly same)I believe OnePlus 9 Pro was the last real OnePlus smartphone.R.I.P. OnePlus and OxygenOS !!By the way this isn't the point of this thread, so let's start the process:Unfortunately you need root access to enable VoLTE, also you need a...Read more