If you're an HTC One M9 owner as well as a fan of CyanogenMod nightlies, here is some good news: CM12.1 nightlies for your device - codenamed himaul - are now available for download.
Aside from the One M9, the nightlies are now also available for three more devices, including the Nvidia Shield Tablet, Shield Portable, and the Lenovo ZUK Z1 - carrying codenames shieldtablet, roth, and ham, respectively.
For those who aren't in the know, as these are nightly builds, they may contain bugs. Also keep in mind that their installation could lead to a bricked device, and worse, could also void your handset's warranty.
I love my HTC One M9 the way it is
Looking at that HTC One M9, it's such a beautiful phone. Such a pity it didn't work out for HTC. Qualcomm, Effff you.!
Unfortunately cyanogenmod stability varies from device to device... rather use rooted stock on a device other than a nexus...