The HTC M9 got his initial ViperOneM9 rom just 3 days ago. Now it already has its first update to 1.1.0.
It contains several bugfixes, but also some new features. One of them, my favorite tweak on the M9 is following:
For this update an OTA is available, to be able to flash it you need to flash this fix here first:
After applyin the fix, you can go to Settings->About->Software Update and Download and Install the OTA.