The Asterisk Development Team have posted details of the Release Cycle:
Asterisk 1.2 was released over 1 year after Asterisk 1.0, which resulted in many users trying to run the development version of Asterisk in a production capacity so that they could take advantage of the new features that had been added. This produced a flurry of extraneous bug reports and caused extra work for the developers as they could not work on changes that would actually cause disruption of the development tree.
In an effort to combat this problem, and to give the community a more predictable release cycle, the process is being organized so that such a long time between releases will never happen again.
Beginning in January of 2006, we will produce new major Asterisk releases on a six month cycle.
The development cycle will be organized in this fashion:
MONTHS 1 - 3
The first three months of the development cycle are when the development branch will be changed most drastically. The tree is open to large architectural changes as well as new feature enhancements and bug fixes.
MONTHS 4 - 5
For the next two months, the development branch will no longer receive architectural changes. New features that are ready to be merged will still be accepted at this point.
The last month is reserved for beta testing. No more features will be accepted for the upcoming release. Beta releases will be made on a weekly cycle, culminating in one (or two) release candidate releases just before the final release.
Asterisk 1.4 is scheduled to be released in the beginning of July, 2006. Once the release is made, a branch will be created. This branch will then receive maintenance for bug fixes only. At that point, the development cycle will start over to prepare for the next major release of Asterisk, scheduled for January of 2007.
The Asterisk Development Team