The following makes up the project's current policy on providing feature updates, security patches, and informal support through the mailing list for current and older software versions of our components. Over time this policy may evolve, and we will announce such changes.
Strict versioning policy mostly ensures deployers can use minor-level upgrades without negative functional impact, so there is rarely a separately designated previous stable release.
We also provide specific guidance on the versioning of Java and C++ components and products and the impact on compatibility.
The current stable release is the most stable release we have of a product. We recommend people deploy this version in production. We MAY add features over time, but will not break compatibility with other releases (over and above any changes made as part of that release). We WILL provide security updates. We WILL produce binary releases on supported platforms. We monitor the bug/issue database and the support mailing list closely for questions, issues, and problems.
A previous stable release is any stable release prior to the current one that has not been moved to the "earlier/unsupported" category below. We WILL provide security updates, but WILL NOT usually add features, and do NOT promise that ongoing changes to the current stable release are backward-compatible with this release. We MAY produce updated binary releases. We monitor the bug/issue database and the support mailing list, but some issues will only be resolvable through an upgrade to the latest stable release, and particularly complex problems may not be addressed if research is required. There might be multiple "previous stable" releases at times, though not often.
Earlier releases should be assumed to be unsupported. We are willing to entertain questions, but in many cases no resolution will be possible without upgrading, and we do not commit to providing any security patches on top of such releases.
A development release is a "point in time" release of code that is under heavy development. We encourage people who wish to experiment with features that have been added to deploy it in a test environment. We will answer questions when we can but it shouldn't be considered a "supported" release.