The release has lots of fixes tracked by bug 627566, and no known regressions.
ia64 stable
amd64 stable
hppa stable
stable for sparc (thanks to Rolf Eike Beer)
arm stable
x86 stable
ppc64 stable
ppc stable
alpha stable
commit 314def93b9bf9ca5423d12336cffdc94a0c99003 Author: Mike Frysinger <vapier@gentoo.org> Date: Tue Jan 9 22:28:46 2018 -0500 sys-apps/portage: mark 2.3.8 arm64/m68k/s390/sh stable Last arch. Closing.