New firmware for the Xperia Z1s (C6916) for T-Mobile has been certified by the PTCRB, moving the build number from 14.4.B.0.37 to 14.4.B.0.56. The ’37’ firmware build brought Android 4.4.4 KitKat to the Xperia Z1s for the first time, so expect this ’56’ build to bring some bug fixes and performance enhancements. We’ll keep you posted on its release.
