Below is some semblance of the release notes:
An upgrade procedure for configurations created in the previous release of crosstool-NG has been introduced with this release.
MacOS is not officially supported in this release.
Support for Alpine Linux as a host is experimental and is known to break
in many configurations (particularly,
*-linux-gnu): GLIBC fails to compile on
a host using MUSL C library when it tries to create some helper applications
to run on the build machine.
CentOS 6 and 7, while still supported, are known to break with recent GDB releases as they require a modern C++ compiler. The G++ included in CentOS 6/7 distributions does not satisfy GDB requirements. Also, “Build and install locales” option in GLIBC cannot be used on CentOS 6/7 build machines: this option requires GLIBC to built for the build machine, and recent GLIBC releases fail to compile on CentOS 6/7.