Just a quick update, today I've just replaced my sim card, and the traditional phone call issue still persist, I come to the conclusion that I can only make a phone call if the line is very very good, if its below than LTE+, the call will either not go through, or the party from the other end can't hear clearly during the calls. Any advice to resolve this issue? As my previous Phone Xiaomi A3 has no issue to make phone calls even if the line is not perfect.

With VoLTE support, the calls will be on the 2G network which is crap and very similar to ART900 or ATUR450 analog calls.

The only way is to change to a better phone with VoLTE support.

You have to forgive me as I am not quite familiar with these terms "VoLTE, ART900 & ATUR450" as I am just a common folk who is just a huge fan of Stock Android, but let me try to level with you guys here, these terms u speak of are the requirements to make a traditional phone calls, and most of the Malaysian Telco has close to none support on Sony phones, therefore the only solution for me to use traditional call method is to change my phone. Man this is a tough pill to swallow ngl, I am feeling kind of sad that I bought the XZ3 and I am unable to fully utilize it.

Really appreciate everyone's reply, I just got this phone recently and not planning to change it anytime soon, if rooting is an option to enable a reliable Phone Calls, then I would like to learn what Rooting is, and what are the issues that I must be aware when rooting a phone. Hopefully someone will an experience in rooting is able to guide me, that would be helpful. As I just found out that "OK Google" Does not work in XZ3 either, really disappointing for a flagship phone to have soo many issues.

Bump

Has anyone here managed to get VoLTE working on the Xperia XZ3? I have tried different kinds of ROM and OEM files on my SOV39 models but to no avail.

Kek just found this thread. Was gonna grab a cheap jepunis sekenhand unit for the more up-to-date android and NFC but then realized it doesn't have a bunch of compatible features like decent voice calls. Thanks guy for saving my money. Guess I'll either go with an older ipong or the S10. My current phone has Volte but its version of android is so old that some of my apps can no longer update. I just need something that's at least 5 versions ahead of what I've got so I can use it for a few more years. That's what I get for buying Huashit I guess...