Does the Z5 support VoLTE?

Planning on getting the Z5 when it comes out, and switching to T-Mobile. I have been hearing recently that some Band 12 LTE phones, which the Z5 is part of, supports the data transfer, but not VoLTE to make calls. This is a reasonably big deal cause the phone doesn't switch to HSPA or GSM to make the call, for some technical reason.

Nothing in the white paper says it does, and google doesn't pull up any relevant results, so just wondering if anyone here knew

thanks!

the links below are for reading about T-Mobile and their B12 VoLTE issues

http://www.androidpolice.com/2015/08...d-smartphones/
http://www.androidpolice.com/2015/08...ill-confusing/