Two new firmware updates have been certified by the PTCRB for T-Mobile US handsets. The Xperia Z3 (D6616) has seen build number 23.1.C.0.399 certified (versus 23.1.C.0.385 currently), whilst the Xperia Z1s (C6916) has seen build number 14.5.B.0.247 certified (versus 14.5.B.0.236 currently).
Given the small change in build number, we don’t expect this to be the Android 5.1.1 firmware update unfortunately. However, we would expect this to fix the Stagefright exploit amongst other bug fixes. We’ll keep you posted once it starts to roll.
Firmware build 14.5.B.0.247 certified for Xperia Z1s (C6916) for T-Mobile
Firmware build 23.1.C.0.399 certified for Xperia Z3 (D6616) for T-Mobile
Thanks Nate and WilliamTell13!