"To accomplish these objectives, the Engineering staff of MySQL
has designed a new ‘milestone’ release model that
differs from the prior methodology utilized for earlier versions of
the MySQL Server. In short, the aim of the milestone model is to
deliver releases of the server every three to six months –
releases that will likely contain new features in each new
milestone, with the quality of each release being, at minimum, RC
(release candidate) in nature. From these milestone releases, a new
GA version of the MySQL Server will be eventually introduced (note
that not all milestones will result in a GA release), with the
timeframes between new GA releases being every 12-18 months.
"In between each milestone drop will be integration
‘windows’ that will allow new, beta-quality features to
be introduced for the next milestone release. It’s important
to understand in regard to these features that the release model
calls for a "rollback" action – if any of the features that
were included during an integration window can't reach the required
quality level by the release date, they are removed and scheduled
for the next milestone. In this same vein, a milestone release (and
subsequent GA versions that are derived from milestone releases) do
not wait for a particular feature to be ready; instead, only
features that are deemed mature enough for inclusion into a new
milestone release from the core software trunk are allowed in and
any feature that does not meet the internally established criteria
simply becomes a potential candidate for the next milestone
drop."
