Short for development, Drupal just like us here at Proctors, will label everything they are working on initially as "dev". It means it is unfinished code, partly made functionality and very much a work in progress and/or a starting point.
This is most definitely not a stage to consider for real world sites. Luckily, you'd probably have to be a developer to know how to get your hands on the code in this early stage anyway.
Drupal 8 has been in Alpha for nearly a year and a half. Alpha releases are the first to come out and be available for general download, though they obviously come with warnings.
To reach Alpha, most of the reported errors must have been resolved and the application working in a reasonable fashion. Usually at this point, most testing has been carried out by the developers themselves and testing is still very much in progress. Bugs and issues will still exist at this point, which will need ironing out.
Again, this is really not a stage to consider for anything production orientated, though most developers who use Drupal will start looking at this point to start learning the changes. The caveat being that there are usually no upgrade paths available from one alpha to another while issues are ironed out, so you shouldn't be doing more than just having a look and learning/testing at this point.
Drupal in particular, has a very key requirements around the number of remaining critical issues and release blockers that must be met to reach the Beta stage. In short though, Beta releases are usually only available once all the critical bugs are solved that might lead to data loss and/or present a security issue. Also by this point, APIs (application programming interfaces - the parts of the system that help other bits talk to it and each other) are stable enough to be frozen for any further development. Upgrade paths usually start to take shape during the Betas.
This is now a great time for those that use Drupal, from a programming point of view, to start having a real look around and start upgrading their own modules and learning the new things available. It's always worth reading the release notes though as upgrade paths, certainly to start with, may be patchy or not work.
As per the above, we still haven't reached a point where Drupal would be recommended for use on live, production sites though. In fact that will only come at full release time.
RC, or Release Candidate
By this point, there will have been no more critical bug reports in the last few Beta releases and the code is considered to be nearly stable. Release Candidates are those that are being considered as candidates for official releases. No more usability changes will be made by this stage. Drupal often go through quite a few Release Candidates in order to ensure the code is fully ready for release.
Now is a good time to start considering using Drupal 8 instead of Drupal 7 for projects. Which ones it is suitable for will still be a bit limited at this point but more on that a bit further down.
Full releases will be version numbered to help later on with updating your site. By this point Drupal 8 will be stable and good to go on production sites.
But this does leave one question? Should you switch straight away? In truth that will most likely come down to two things:
- How much functionality your site will need and
- How many contributed modules have been upgraded to Drupal 8, which are needed to provide the functionality you require.
Luckily this time round, the functionality available in Drupal 8 "out of the box" is significant, so the wait for contributed modules to upgrade will hopefully be shorter. For example, Drupal 8 will come with in-place WYSIWYG editing now that the CKEditor has been put into Drupal 8's core. Views, a very powerful module used on almost every site for pulling out lists of content, amongst other things, has now been put into Drupal 8's core as well. Plus lots and lots of other great features from "mobile ready out of the box" to full, true, multilingual capabilities. If you want to read more about what will be in Drupal 8, have a look here: