New version has been released on September 11, 2017. Before that another new version has been released, 3.22.4, on June 13, 2017. Bugfixes and features. https://github.com/shimmerproject/Greybird/releases/tag/v3.22.4 https://github.com/shimmerproject/Greybird/releases/tag/v3.22.5
Thank you for the bump request. You can help the maintainer with further information: Does a simple bump [1] work on your system? Chances are high, because a first look on the bump revealed only small changes. [1] https://wiki.gentoo.org/wiki/Custom_repository#Simple_version_bump_of_an_ebuild_in_the_local_overlay
Yes, simple version bump works and I don't see any issues so far. New version contains simple theme for Gnome Shell and I didn't check it as I don't use Gnome. Current ebuild installs Gnome Shell theme.
3.22.6 is out and has some important fixes for gtk3!
commit d4aa945dcea4e488598f4ba3ca5f7b00d7deed98 Author: Jason Zaman <perfinion@gentoo.org> Date: Mon Apr 2 15:35:42 2018 +0800 x11-themes/greybird: bump to 3.22.8 Package-Manager: Portage-2.3.24, Repoman-2.3.6