What are alpha and beta releases, and release candidates?
Before every official "x.0" stable release of a new major version of Drupal core, there are usually a handful of alpha releases, beta releases and release candidates that are made available. These releases are not yet stable enough for production use, but are essential milestones on the way towards the official release. They allow a much wider pool of users to test the latest code and provide feedback before the official stable release. These releases should only be downloaded and used by developers very familiar with Drupal or those wishing to help find bugs in the software.
The guidelines below are for Drupal core. Some maintainers of contributed modules and themes might choose to provide alpha or beta releases or release candidates of their projects (though this is not required). You should read the release notes carefully in these cases, since the details might vary across projects, though the basics explained here should hold (an "alpha" is less stable than a "beta", which is less stable than an "RC", etc).
- Alpha releases