CyanogenMod is likely the most popular custom ROM ever made for an Android device, whether that be a tablet, smartphone or even a set top box. In 2013, Cyanogen decided to branch off of CyanogenMod so there is now an open-source version known as CyanogenMod, and then Cyanogen Inc., with Cyanogen OS is proprietary and available for their own devices. One of those is the ZUK Z1. CyanogenMod is a vanilla Android custom ROM with plenty of customization options available for the user. It's available with most flagships, and even some mid-range and low-end devices, and allow the user to still get updates, months if not years after the carrier or manufacturer has ended pushing updates to it.
Today, CyanogenMod has started pushing out official builds for a number of devices. This includes the HTC One M9, NVIDIA SHIELD Tablet, SHIELD Portable and the ZUK Z1. Now the ZUK Z1 already runs on Cyanogen OS (a slight difference but not much from CyanogenMod). In their announcement on Google+, the CyanogenMod team also announced that security updates for this month have been merged into the CyanogenMod 11 and 12.1 branches and builds. So you will get the latest security patch. Always important.
The CyanogenMod team also teased that Marshmallow is coming soon, which we heard from Cyanogen's founder, Steve Kondik at the Big Android BBQ earlier this week. Although Kondik was referring to Cyanogen OS and not CyanogenMod. However, CyanogenMod shouldn't be too far behind Cyanogen OS. As always with the CyanogenMod team, no ETA's were given. But we should begin seeing nightlies for some devices with Marshmallow in the very near future. In the next few weeks if not days. It'll likely begin with Nexus devices and move out to Motorola, HTC, LG and Samsung devices next.
If you're looking to install CyanogenMod, you can head to the source link below and download the latest build for your device. Remember you will need to be rooted - which does void your warranty. Additionally, you'll need to flash the latest Gapps. For legal reasons, vanilla Android or AOSP custom ROMs can't include Google apps in their builds. So those have to be flashed separately.