Tipsters alerted us to the download earlier this morning, but T-Mobile waited until later in the day to offer up a update on their support page describing what was in the 38.60MB file. It stated:
Beginning July 31 the Samsung Galaxy S 5 will have a software update to Android 4.2.2/Baseband G900TUVU1BNG3. Customers already on VoLTE software are being notified of the OTA software update. Customers not on a previously released VoLTE software must manually request the update via Wi-Fi due the file size. A manual update via Samsung Kies is also available. This update provides features and improvements.
Yep, that's pretty vague (and with an incorrect 4.2.2 software version), but it is there. In June, T-Mobile launched an update to the Galaxy S5 and the Note 3 that added support for customers on its VoLTE network. If you got this small update, did you notice anything different with the Galaxy S5?
Source: T-Mobile Support Page