If you've been eagerly awaiting the Android 4.4.3 update for your T-Mobile One M8, wait no more: it has arrived. The update brings a slightly newer version of Android, security fixes, wireless optimizations, and updates to several stock HTC applications. If you're not able to pull the update over the air, XDA user sapplegater has uploaded the OTA to Mega.
As always, if your device is rooted this particular update might be one to skip - the ever-present "security fixes" packed in this OTA often plug up exploits that allow root access, and Android roots are becoming increasingly hard to discover as Google and OEMs refine their software.