Any LTS versions of Ubuntu (LTS: Long Term Support) carries a particular importance when comparing with the standard releases because a LTS is aimed at corporations and other similar professional environments where both stability and security is most needed.
Now Ubuntu’s popularity is increasing little by little and as a result the developers have decided to support the upcoming 12.04 LTS up to five years (before it used to be three years).
Like with any other software release, there’s a certain protocol that most GNU/Linux distributions follow prior to a new OS release.
It starts with the “Alpha” (there are usually more than a single Alpha versions) then to “Beta” (again multiple versions), then to the release candidate (which is like an almost official release because it usually comes out few days before the original release)) and then big official release.
This was how Ubuntu too used to do it but according to their official Release Schedule Wiki page, for some reason they’ve removed the “Release candidate” version which was scheduled at April 19, 2012 (a week before the official release).
And according to this new release schedule although the official release date or any other have not changed but now the last “test” release before the official one is actually the “Beta 2” (scheduled at March 29, 2012).
This may not be a big thing or could be a temporary change … but it’s always nice to have an “almost ready” ISO image just before it goes official as a safety precaution (last minute bugs etc), don’t you think?