Update #2: T-Mobile has started updating support pages with a clarification on those Wi-Fi calling enhancements. The phones now have support for Gogo inflight texting, a feature the company announced as part of Un-Carrier 7.0.
Update #1: The Galaxy S5 got some love, too.
Google isn't the only company lumping big updates on Wednesday. T-Mobile is sending out Android updates to four, count 'em, four phones on its network.