@rohitpatil This hurts to write because I had to buy yet another OP6T when I did the research. The answer is basically "no". Although the OPO has the physical architecture to handle some 4G bands, it can't handle VoLTE and no OS does it.
If 3G will still be available where you are, your phone should be fine. Unfortunately, for AT&T customers (in the US at least) it won't work at all.
Unless they just lied and the phone will work fine on Feb 22.