The official M12 Snapshot build of CyanogenMod 11 has been released last week for multiple HTC smartphones such as the HTC One M7, One M8, One S, One Mini and the One Max variants. If you're a fan of this popular custom ROM and you wish to tinker with your device's ROM, then the CM 11 M12 build is your best bet for a stable operating system.
The CM 11 M12 Snapshot is based on the latest Android 4.4.4 KitKat and it will most probably be one of the final builds based on it. CyanogenMod team is currently working on the Android 5.0 Lollipop AOSP releases. Before the end of this year we should surely see the release of CM 12 Nightlies based on Android 5.0. But, note that not all HTC smartphones will support the future CM 12 and you should carefully follow the progress by checking the CM Google+ page here or their Twitter account here.
CyanogenMod 11 M12 build doesn't pack too many new features and it is mostly a stability update that should offer an improved CM experience. There are some security improvements and fixes that will add Google patches for the "POODLE vulnerability in SSLv3". Some other changes have been added for multi-sim smartphones. As I said, this M12 release is not a big update and feel free to tell us in comments if you can find important new features that aren't listed by the CyanogenMod team in their changelog.
The CM 11 M2 custom ROM is based on stock Android 4.4.4 KitKat, but it still packs tons of other CM features that were added since the M1 Snapshot build of CyanogenMod 11 release. You should install these M-Snapshot Android 4.4.4-based builds instead of CyanogenMod's Nightly release, as those aren't very stable and you will be notified every single time when a Nightly build is made available for download.
Grab the CM 11 M12 Snapshot ROM build for your HTC device from here. Use the "ctrl+f" command in order to find your HTC device's model at CyanogenMod's Download website. Make sure to install Gapps zip for Android 4.4.x ROMs after the ROM is installed. Also, remember that these builds are working with rooted devices only and you can flash them using CWM or TWRP custom Recovery. Tell us in comments if you've installed one of these builds and detail which feature has impressed the most while testing the ROM.