Read the official Contao announcements.
Adjustment of the Contao release cycle
by Leo Feyer
Due to various dissatisfactions with the release cycle, which has been relsolved in 2009, we have readjusted it in consultation with the community and, on this occasion, added long term support releases.
Major, minor and maintenance versions
The previous distinction between major, minor and maintenance releases will remain, although maintenance releases will be called "bugfix releases" in the future, to stronger emphasize their purpose. Hence the previous 3-digit version numbers (e.g. 2.10.1) will remain as well.
A major release is a version change from e.g. Contao 2 to Contao 3. It includes new features, mostly changes of the API, the data structure and the templates as well as a new interface or a modified/enhanced control concept. Third-party extensions will most likely not work without adjustments. Existing websites cannot be updated without adjustments, either.
Before a new major version is released, there is a beta and RC phase. We are planning to release a new major version every two years. The first release candidate will be published shortly before the Contao conference, the final release in the summer of the same year.
A minor release is a version change from e.g. Contao 2.9 to Contao 2.10. It includes new features and can include changes of the API, the data structure or the templates. Fundamental changes e.g. of the control concept are not to be expected though. Third party extensions should be checked. Existing websites can normally be updated with a few smaller adjustments.
Before a new minor version is released, there is a short beta and RC pahse. Minor versions are released as required and are not scheduled.
A bugfix release is a version change from e.g. Contao 2.10.0 to Contao 2.10.1. It does not include new features or changes of the API or the data structure – unless fixing a defect requires such changes. Third party extensions can most likely be used further. Existing websites should be upgradeable without adjustments.
Before a new bugfix version is released, there is no beta or RC phase but only a short test phase on the basis of the current SVN version (trunk). The announcement is usually made on Twitter, either by the Contao main developer, @leofeyer, or by @contaocms.
Long term support release (LTS release)
LTS releases are long term releases which will be updated with bugfix versions for at least 18 months (depending on the release date of the next minor version).
So far, minor versions were only supported until a new minor version was released; the release of version 2.10 was also the end of life of version 2.9. A long term support release, however, will be supported with bugfixes during its whole life, no matter how many minor or major versions are published in the meantime.
The following chart shows an example release cycle:
Most likely, the first LTS release will be version 2.11. The release dates in the above chart are non-binding example dates only. Release cycles may vary.
Special treatment for hooks
Hooks are interfaces in the Contao core, which can be used as entry points for third-party extensions to modify the program flow. Since adding a hook is an API change, this will only be done in major and minor versions in the future. To still allow a promt usage, we will provide patch files in the ticket system, so you can adopt the functionality before the actual release.