In case you own an HTC One M9, then you might be well aware of CyanogenMod Nightlies. Fans of CyanogenMod Nightlies has good news as the team is now expanding their selection to four devices, namely Lenovo ZUK Z1, NVIDIA's SHIELD Portable, SHIELD Tablet, along with HTC One M9.
As usual, Cyanogen makes use of code names to arrange its build. HTC One M9 is coded as "Himaul," Z1 is termed as "Ham," SHIELD Portable is coded as "Roth" and SHIELD Tablet is named as "Shieldtablet."
All of these four devices are currently build on Cyanogen nightly mode 12.1. Also, there are chances that these modes may or may not add to the upcoming releases. CM team has always made it to a point to ensure that they do not graduate phones or tablets to much more stable location until the stability test have been done.
Also, the team employs usability tests and this is one important factor as to why HTC One M9 build works only for international models. HTC One M9 and ZUK Z1 employs AOSP based ROMs that makes it preferable and desirable to users, only if it is available to manufacture skins as an alternate; however, users who own SHIELD portable or SHIELD tablet would prefer to avoid the same.
Meanwhile, NVIDIA takes responsibility to update its first party software on a regular basis to ensure that they run clean as always. Also, NVIDIA employs the new version of Android Lollipop 5.1 making the device easier to use.