The 2.21 series release notes contain important changes in this release series.

Security Fixes

• LOW: High CPU usage could be triggered by a specially crafted request to the SVN bridge resulting in Denial of Service (DoS).
• Packages have been updated to the latest security versions.

Known Issues

• On a freshly set up GitHub Enterprise Server without any users, an attacker could create the first admin user.
• Custom firewall rules are not maintained during an upgrade.
• Git LFS tracked files uploaded through the web interface are incorrectly added directly to the repository.
• Issues cannot be closed if they contain a permalink to a blob in the same repository where the file path is longer than 255 characters.
• When "Users can search GitHub.com" is enabled with GitHub Connect, issues in private and internal repositories are not included in GitHub.com search results.
• Security alerts are not reported when pushing to a repository on the command line.

Thanks!

The GitHub Team