There are multiple supported feature frozen releases of Asterisk. Once a release series is made available, it is supported for some period of time. During this initial support period, releases include changes to fix bugs that have been reported. At some point, the release series will be deprecated and only maintained with fixes for security issues. Finally, the release will reach an its End of Life, where it will no longer receive changes of any kind.
The following table shows the release time lines for all releases of Asterisk, including those that have not yet reached End of Life. If you do not see a release series listed here, then it has already reached EOL.
Security Fix Only
New releases of Asterisk will be made roughly every six months. Releases marked as LTS releases will be much less frequentonce a year, alternating between standard and LTS releases. Within a given release series that is fully supported, bug fix updates are provided roughly every 4 weeks. For a release series that is receiving only maintenance for security fixes, updates are made on an as needed basis.
If you're not sure which one to use, choose either the latest release for the most up to date features, or the latest LTS release for a platform that may have less features, but will usually be around longer.
The schedule for Asterisk releases is visualized below (which is subject to change at any time):
For developers, it is useful to be aware of when the feature freeze for a particular branch will occur. The feature freeze for a branch will occur 3 months prior to the release of a new Asterisk version, and a reminder announcement will be posted to the asterisk-dev mailing list approximately 60 days prior to the feature freeze. Asterisk versions are slated to be released the 3rd Wednesday of October. The feature freeze for a branch will occur the 3rd Wednesday of July. An announcement reminder will be posted to the asterisk-dev mailing list the 3rd Wednesday of May. Feature freeze consists of the creation of two branches: One for the release series and one for the initial release. Features can continue to be placed into the release series branch according to policy but the initial release branch will be frozen.
Feature Freeze Announcement Reminder
3rd Wednesday of May
Feature Freeze of Asterisk Branch
3rd Wednesday of July
First Release of Asterisk from Branch
3rd Wednesday of October