There is nothing for Nokia to push, if your SIM has been provisioned it either works or it doesn't. In the UK the Nokia 8 works with VoLTE on EE but doesn't work with VoLTE on Three with Three stating you have to have purchased your handset from them and therefore be running their firmware for VoLTE to work.
Only iPhones (since the 5s) work out of the box with VoLTE on all networks, with Android it is pot luck.
I am in Bangalore. Please reach out to the nodal or appellate officer though email.