Releases v3.8.3.1 and v3.9.2.0 are tagged and available on Github. Download tar/zip files from https://github.com/gnuradio/gnuradio/releases, or git clone your preferred tag/branch, and enjoy!
The most visible changes for users: - Both releases have a number of updates to GRC. - v3.9 now includes gr-soapy. See https://wiki.gnuradio.org/index.php/Soapy for more details.
See the release notes on the Github releases page or the CHANGELOG.md in each release for a longer list.