Stability branches

Note: Stability branches now produce official point releases, available from the main page. This page describes the development philosophy in more detail.


The stability branch series is an official fork of the CHICKEN Scheme core which backports certain useful bugfixes and minor features from the future to "stable" maintenance versions.

Each stability branch is branched off a tagged version of the master branch, such as 4.7.0, and named like stability/4.7.0, where 4.7.0 represents the branch point. Stability branches may also sprout from development versions such as 4.7.3, depending on demand.

Releases for stability/4.7.0 have version numbers like 4.7.0.x (for example, and are tagged in the repository with this version number. The tag and version number are updated together. Prior to, version numbers had an -st suffix to denote their unofficial status.

NEWS.stability in the repository contains a detailed list of changes in each release, while NEWS gives a more friendly overview.



The stability/4.8.0 branch is based on 4.8.0 and provides the official 4.8.0 point releases (such as

Downloads are available on the releases directory.


The stability/4.7.0 branch is recommended for general use and is based on CHICKEN 4.7.0.

The latest version is (download, NEWS, detailed changes).

Obtaining the code

From tarball (4.8.0.x)

Downloads are available on the main page.

From tarball (4.7.0.x)

Stability tarballs can be built from scratch without an existing copy of CHICKEN. See the README for build instructions.

From git

To clone the stability branch into chicken-core-stability/:

git clone git:// --branch stability/4.7.0 chicken-core-stability

If you already have a copy of the git repository that you'd like to use, ensure you are up to date and then switch to the stability/4.7.0 branch:

git fetch
git checkout stability/4.7.0

To checkout a particular version:

git checkout

HEAD may have had patches applied after the last tag. The version number will be the same and it should be safe to use HEAD, but you can checkout from the tag if desired.

Support policy

There is not yet a formal support policy with regards to how long an older stability branch will be maintained once a newer one is available. Generally, we encourage upgrading to the latest release.


Jim Ursetto