Drupal 8.4.0 release candidate phase

The release candidate phase for the 8.4.0 minor release begins the week of September 4. Starting that week, the 8.4.x branch will be subject to patch release restrictions. Closer to the 8.4.0 release on October 4, we will limit the changes to critical bugfixes and other high-priority changes. You can help by ensuring that the issue priority is set correctly for major-priority issues, and that the branch field is set to 8.5.x (for disruptive changes) or 8.4.x (for patch-release-safe bugfixes) as appropriate.

8.4.0 provides stable, production-ready releases for several modules that were previously experimental, including Workflows, Datetime Range, Layout Discovery, Media, and Inline Form Errors. The release also includes several critical bug fixes and many other improvements for REST, content moderation, authoring experience, performance, and automated testing. You can read a detailed list of improvements in the announcement of alpha1.

Minor versions may include changes to user interfaces, translatable strings, themes, internal APIs like render arrays and controllers, etc. (See the Drupal 8 backwards compatibility and internal API policy for details.) Developers and site owners should test the release candidate to prepare for these changes.

8.5.x will remain open for new development during the 8.4.x release candidate phase.
Drupal 8.4.0 will be released on October 4th, 2017.

No Drupal 8.3.x or 7.x releases planned

September 6 is also a monthly core patch (bug fix) release window for Drupal 8 and 7, but no patch release is planned. This is also the final bug fix release window for 8.3.x (meaning 8.3.x will not receive further development or support aside from its final security release window on September 20). Drupal 8 sites should plan to update to Drupal 8.4.0 on October 4.

For more information on Drupal core release windows, see the documentation on release timing and security releases, as well as the Drupal core release cycle overview.