The T-Mobile version of the HTC One M8 has received an update to enable Extreme Power Saving Mode. The feature, which was announced at launch, had to be approved by carriers before it could be pushed out to the devices, and that's just what happened today with T-Mobile's One M8.
The update clocks in at a hefty 229.8MB and also improves overall battery life and Wi-Fi performance.
For the unacquainted, Extreme Power Saving Mode kicks in at a default of 10% battery remaining. It throttles back the CPU, dials down screen brightness, turns off haptic feedback, switches off data when the screen is off, and only allows 'essential' apps (e.g. phone, messaging, mail, calendar, and calculator) to run. This is all with the goal of maximizing battery life for hours of addition, if limited, use.
Thanks to Don for the tip!