I have asked the same for my country (Spain) and they do nothing .. it is unfortunate. I do not understand it is because a phone that has cost me € 1000, does not have VolTE. And as you say
@alfi.nagashi , phones less than € 100 have it .. Please enable VolTE more quickly. They go to a country for update ... at this rate, change phone before they enable it ..
Please enable it quickly. If not, users will switch phones before they enable it and it won't be worth the work anymore.