The 2.2 series release notes contain important changes in this release series.

Security Fixes

• HIGH Read access to public API endpoints of private-mode instances and to specific reporting endpoints can be authenticated by connecting via local trusted ports. This authentication could be bypassed by manipulating specific HTTP headers and lead to information disclosure.
• Kernel and packages have been updated to the latest security versions.
• Mediawiki Math markup within Gists and repository files with the .mediawiki suffix could leak information to the Google Chart API when they were displayed.

Known Issues

• Repositories that are in an incomplete state, which is a rare problem, can cause the migration to the new repository disk layout to fail.
• Enqueued background jobs are sometimes not purged when a repository is deleted.
• Organization invitation emails are sent from the configured support email address rather than the no-reply address.
• We can fail to properly create the key for the secure connection between a high availability replica and the primary, which causes replication setup to fail.
• Management console sessions can expire too quickly for Safari users.
• Gist repositories are not garbage collected by the maintenance scheduler.
• Gist profile pages don't have proper styling when subdomain isolation is disabled.
• Custom firewall rules aren't maintained during an upgrade.
• Dashboard activity feed links point to wrong hostname after restoring from backup if the hostname has changed.
• On a freshly set up GitHub Enterprise without any users, an attacker could create the first admin user.
• Jobs stuck on code indexing can delay other jobs from running.
• Replication setup fails for IPv6 hosts.
• The management console settings interface doesn't clearly show if you have previously uploaded certificate files or a private key.
• Images uploaded to issues save with an absolute URL, so they can be broken if the hostname changes.
• Gists can't be created when using Safari 8.x in Private Mode.
• Deleting a user doesn't delete their gists, which can cause problems with replication.
• In our instructions to merge a pull request on the command line, we show the steps to merge using the Git protocol even when private mode is on. Private mode forces authentication but the Git protocol is unauthenticated so the steps will always fail. We also don't show the steps to merge using SSH.
• We incorrectly redirect to the dashboard if you access GitHub Enterprise using an alias while in private mode. This might happen if you set a fully qualified domain name but the subdomain resolves correctly.
• We display the time in the scheduled maintenance banner in UTC instead of the viewer's timezone.
• Users with LDAP DNs longer than 255 characters are suspended if LDAP Sync is enabled.
• Viewing raw files in repositories owned by a user or organization named "github" fails with a 400 error. (updated 2015-12-15)
• Trying to add a file to a repository with Subversion 1.9 clients incorrectly detects the file already exists and fails. (updated 2016-01-14)

Thanks!

The GitHub Team