The maintenance policy defines how long the various versions of TYPO3 4.x are supported and at which level. The release of new 4.x versions is not covered by this policy. The general rule is the following:

• the active development is being done on version 4.x+1.
• the current stable branch is 4.x. It is actively maintained. This means that all known and patched bugs are fixed upon decision by the Release Manager. All security patches are applied.
• the previous stable branch is 4.x-1. It is only partially maintained. This means that all security patches are applied. However other bugs are fixed only at the discretion of Core Team members and upon decision by the Release Manager.
• the next older branch is 4.x-2. Only critical security fixes are applied. No other bugs get fixed anymore.
• older branches are unsupported.
• a version may be declared as having Long-Term Support (LTS). In this case it supported for 3 years no matter what other releases happen in the meantime. TYPO3 4.5 will be LTS.

Every month a decision is made whether a new maintenance release should happen for any of the supported branches or not. The decision is taken by the Release Manager and is based upon the number of bugs fixed and their importance. Security patches are also a criterion for release, of course.

The chart below shows how this applies to the current and upcoming TYPO3 versions.