DragonFly BSD 5.0
https://www.dragonflybsd.org/release50/ [www.dragonflybsd.org]
2017-10-16 23:09
Preliminary HAMMER2 support has been released into the wild as-of the 5.0 release. This support is considered EXPERIMENTAL and should generally not yet be used for production machines and important data.
Plus more of course.
source: L