XZ Utils 5.2.1 is available at <http://tukaani.org/xz/>. Here is an extract from the NEWS file:
* Fixed a compression-ratio regression in fast mode of LZMA1 and LZMA2. The bug is present in 5.1.4beta and 5.2.0 releases. * Fixed a portability problem in xz that affected at least OpenBSD. * Fixed xzdiff to be compatible with FreeBSD's mktemp which differs from most other mktemp implementations. * Changed CPU core count detection to use cpuset_getaffinity() on FreeBSD. -- Lasse Collin | IRC: Larhzu @ IRCnet & Freenode