An update is available for your m8. It’s based on the latest 3.28.401.7 base running Android 4.4.4.
Ensure you update your firmware to the latest one. Instructions you will find here:
ViperOneM8 3.0.0 requirements
…othewise your phone won’t boot.
Notice: No support for verizon and sprint in that release. Once Sprint and verizon releases a 4.4.4 based rom, supported will be readded.