OxygenOS 3.5.4 represents the second software update that the OnePlus 3T is receiving since the phone first hit markets around the world, back in November. Of interest to US owners of the 3T, the new update optimizes the handset to work better on T-Mobile's network.
Besides optimization for T-Mobile, the update includes: system stability enhancements, optimizations to reduce lag when the battery is below 5%, enhanced battery saving mode, optimized Bluetooth connectivity for Mazda vehicles, fixed Flash usability issue in WhatsApp, and various other bug fixes.
Unfortunately, OxygenOS 3.5.4 is still based on Android Marshmallow, which means OnePlus is not yet ready to bring Android 7 Nougat to its handsets. Nevertheless, both the OnePlus 3T and OnePlus 3 could be updated to Nougat before the end of this month.