There are quite a few features in Sense that make the HTC One M8 stand out from their counterparts. One of the features that is really useful is the Power Saver feature. It changes some of the performance settings on your device for battery optimization automagically just by toggling it on. It adds some precious time to your battery life. The only real downside to this is the fact that it imposes a power saver icon in your notification bar. To get rid of this annoying icon you will need to be S-Off, rooted, and will need to run a few commands in the terminal emulator app.
-Open the terminal emulator.
-type "su" to grant super user permission
-type "pm disabled com.htc.htcpowermanager/.powersaver.PowerSaverNotificationReceiver"
-Enjoy
via XDA