WordPress Beta Tester allows you to get involved with the WordPress development process by making it easy for you to get early access to nightly builds and beta releases using the core upgrader.

The choice you have is:

  • Point release nightlies – This contains the work that is occurring on a branch in preparation for a x.x.x point release.  This should also be fairly stable but will be available before the branch is ready for beta.
  • Bleeding edge nightlies – This is the bleeding edge development code which may be unstable at times. Only use this if you really know what you are doing.

Once you enable the plugin it will by default switch your blog to the “Point release” stream and if you want to switch to the “Bleeding edge” stream then you will need to go to the Tools … Beta Testing page and configure the plugin there:

Please note: Once you have switched your blog to one of these beta versions of software it will not always be possible to downgrade as the database structure maybe updated during the development of a major release.

More information about the plugin can be found on the original announcement post and in WordPress Extend.