Wi fi calling settings and updates

I have a Ulefone S8 Pro. I used the Three network which had a wi fi calling app called 'Three in Touch' which let me make calls vis any wi fi connection. THREE now only supports this on phones you buy from them.

Question 1: Does this phone have wi fi calling and if so how do I enable it?

Question 2: the phone runs on Android 7 How do I upgrade to the latest version as I don't seem to get automatic updates.

Many thanks

Paul