Note: You are currently viewing documentation for Moodle 1.9. Up-to-date documentation for the latest stable version is available here: Moodle versions.
Understanding Moodle versioning scheme may help you to choose a correct place to fetch source code from for upgrade. Also, referring to a correct version is important when reporting a bug in the tracker.
Major and minor versions
Moodle version number consists of three numbers separated by dot, for example 1.9.11 or 2.0.2. The first two numbers, like 1.9 or 2.0, represent so called major version. The third number distinguishes minor versions within the same major version. When a new major version is released, it starts with the minor version set to 0 (zero). So Moodle 2.0.1 was the first minor update of Moodle 2.0.0.
Generally, Moodle HQ team maintains the two most recent major versions of Moodle with some exceptions - like there is a longer term support promised for Moodle 1.9.
Versions and branches
Moodle developers use source code management (SCM) system Git to track changes in the code. As in many SCMs, the history of changes in Git is represented via so called branches. You can consider a branch as a labeled sequence of source code changes.
There is a branch created for every major version of Moodle. All Moodle 1.9 versions come from MOODLE_19_STABLE branch and all Moodle 2.0 versions come from MOODLE_20_STABLE branch. There is also a main development branch called master that holds the changes for the next future version. At the moment, the changes on the master branch will be included in Moodle 2.1 release.
Since the version 2.0, Moodle aims to release the new major version every six months or so. See Roadmap page for a schedule.
Minor versions are released irregularly, typically when there is a significant amount of fixes since the last version or if there is a security issue fixed (in either Moodle itself or in some external library it uses).
In the meantime between two releases, Moodle HQ team publish updates for the most recent stable versions. These updates are published every week, usually on Wednesday. They are known as weekly builds and are identified by a number like 20110323. That is a timestamp in a form YYYYMMDD when the weekly build was released. These weekly builds are labelled with a version number suffixed with a plus sign. So 2.0.2+ denotes some weekly build extending the 2.0.2 minor release.
Source code maturity levels
During its life cycle, the Moodle code branch goes through several maturity levels.
- At the beginning, the branch is considered as being in alpha state. During this period, new features are added to the branch. API and database structure may change as needed. These versions are intended mainly for developers as nothing is guaranteed (the version may or may not install and upgrade, for example).
- When it is decided that no new feature will be added to the branch (so called feature freeze), beta maturity level is reached. Developers focus on testing, bugs fixing and stabilizing the branch.
- When all known critical and blocker bugs are fixed and no new bugs are reported for some time of testing, a preview version of the branch can be released as so called release candidate. When the first release candidate version (RC1) has been published, release candidate maturity level is reached. During this period, several RC versions can be issued, for example 2.1RC1, 2.1RC2, 2.1RC3 etc.
- Finally, the new major version is released and the branch reaches stable maturity level. From now on, the database structure and API do not change on this branch. A corresponding MOODLE_xx_STABLE is created and minor versions and weekly builds are created off it.