In a recent forum post on Moodle.org development forums, Moodle’s Development Process Manager ‘Marina Glancy‘ posted a notice for all the Moodle developers about the cut off date for code-freeze for upcoming Moodle 2.9 version.
So, the Moodle 2.9 code will be freezes by 06th April 2015. The code freeze is a point after which no new code (only fixes to existing code) is accepted until beyond the release. This stabilization allows for QA testing and means developers are able to respond rapidly to bugs found.
So, after the code freeze there will be 2 more stages for Moodle 2.9 before it is available as a stable release.
QA, bug fixing, continuous integration: A period after the code freeze where quality assurance testing takes place. No new code is added, which means developers are able to respond rapidly to bugs found. Integration becomes continuous, meaning that failed QA tests can be re-run within days rather than having to wait for the weekly release.
Release candidate: A point prior to the full release where a candidate is made public for wider testing.
For more details about the development process, please check out this link: http://docs.moodle.org/dev/Process#Events_during_cycle