The update weighs in at a C section inducing 550MB, and takes users to software version 6.09.401.5. Like the Android 4.4.3 update we've seen for the HTC One (M8), this update includes improvements to the Camera, Settings, Gallery and HTC Sync manager. Other enhancements are coming to BoomSound, the Quick Setting feature, Motion Launcher, Wi-Fi, network connectivity and Bluetooth.
The update will probably follow the path of the update for the HTC One (M8), which means the European update should continue in the days ahead, to be followed by carrier-specific updates in the states.
source: AndroidPortal (translated) via GSMArena, AndroidAuthority