The current maintainer responsible for planning and performing releases is Ingo Schommer (ingo at silverstripe dot com).

Our most up-to-date release plans are typically in the roadmap. New features and API changes are typically discussed on the core mailinglist. They are prioritized by the core team as tickets on open.silverstripe.org.

Release dates are usually not published prior to the release, but you can get a good idea of the release status by reviewing the release milestone on open.silverstripe.org. Releases will be announced on the release announcements mailing list.

Releases of the cms and sapphire modules are coupled at the moment, they follow the same numbering scheme. Module releases are documented separately in module-releases.

• Versions are numbered by major version number, minor version number, and micro version number, in the form A.B.C (e.g. 2.4.1)
• A is the major version number, which is only incremented for major changes and core rewrites, lots of them won't be backwards compatible.
• B is the minor version number. It is incremented for our typical releases with new features and bugfixes. We strive for few changes to be backwards incompatible, and will deprecate any APIs before removing them.
• C is the micro version number, incremented for bugfixes, minor enhancements and security fixes. Unless security-related, all changes will be fully backwards compatible to the minor version number.
• Major and minor releases have an alpha cycle, which is a preview developer release which that see major changes until release. It is followed by a beta cycle, which is feature complete and used by the wider development community for stability and regression testing. Naming convention is A.B.C-alpha and A.B.C-beta.
• Major, minor and micro releases can have one or more release candidates (RC), to be used by the wider community. A release candidate signifies that the core team thinks the release is ready without further changes. The actual release should be a identical copy of the latest RC. Naming convention is A.B.C-rc1 (and further increments).

So far, major releases have happened every couple of years. Most new releases are minor version number or micro version number increments. So far, we only had one major release, from the 1.x to the 2.x line.

Minor releases have happened about once every 18 months. For example, 2.3 was released in February 2009, followed by 2.4 in May 2010.

These releases will contain new features, general enhancements and bugfixes. APIs from previous minor releases can be deprecated, but will stay available for one more minor release. So, if an API is deprecated in A.B, it will continue to work in A.B+1, and removed in A.B+2.

An example: Say we'd want to rename BasicAuth::requireLogin() to follow our coding conventions, which is BasicAuth::require_login(). The method was introduced in 2.1, we've made the change in 2.3?

• 2.3 would've marked the method as @deprecated, and documents it as an API CHANGE in our changelog. The old method continues to work, but will throw an E_USER_NOTICE.
• 2.4 would've removed the method, also documenting it as an API CHANGE, and mentioning it in the upgrading guidelines.

Exceptions to the deprecation cycle are APIs that have been moved into their own module, and continue to work with the new minor release. These changes can be performed in a single minor release without a deprecation period.

Micro releases are issued about every two months for the latest release, typically for security reasons. You can safely upgrade to those releases (after reading the upgrading guidelines). For example, 2.3.6 was released in February 2010, followed by 2.3.7 in March 2010.

At any point in time, the core development team will support a set of releases to varying levels:

• The current development trunk will get new features and bug fixes that might require major refactoring before going into a release (Note: At the moment, bugfixing and feature development might happen on the current release branch, to be merged back to trunk regularly).
• Applicable bugfixes on trunk will also be merged back to the last minor release branch, to be released as the next micro release.
• Security fixes will be applied to the current trunk and the previous two minor releases (e.g. 2.3.8 and 2.4.1).