CyanogenMod 13, based on Android 6.0 Marshmallow, was formally released back in March, but it’s only just arriving for some devices, in the form of nightlies. The most notable of these devices are probably the original HTC One and the Wileyfox Spark, plus the Spark X – the Spark’s bigger, more powerful brother.
The HTC One is being bumped up from CM12.1, which was based on 5.1 Lollipop, while the Spark and Spark X are receiving their first taste of the custom ROM, albeit not their first Cyanogen flavored taste though, since they run the in-house Cyanogen OS, which has recently been killed off.
A bunch of devices receive CyanogenMod 13 updates, HTC One and Wileyfox Spark among them was written by the awesome team at Android Police.