This page describes the release process used with MCUboot.
MCUboot uses semantic versioning, where version numbers
MAJOR.MINOR.PATCH format with the following guidelines on
incrementing the numbers:
MAJOR version when there are incompatible API changes.
MINOR version when new functionalities were added in a backward-compatible manner.
PATCH version when there are backward-compatible bug fixes.
We add pre-release tags using the format
In the documentation, we mark an MCUBoot development version using the
Before making a release, update the
to describe the release. This should be a high-level description of
the changes, not a list of the git commits.
Provided that changes going into the release have followed the
contribution guidelines, this should mostly consist of collecting the
various snippets in the
docs/release-notes.d directory. After
incorporating these snippets into the release notes, the snippet files
should be removed to ready the directory for the next release cycle.
Before each release, tags are made (see below) for at least one release candidate (a.b.c-rc1, followed by a.b.c-rc2 and the subsequent release candidates, followed by the official a.b.c release). The intent is to freeze the code and allow testing.
During the time between the rc1 and the final release, the only changes that should be merged into the main branch are those to fix bugs found in the RC and in the Mynewt metadata, as described in the next section.
imgtool is released through pypi.org (The Python package index).
It requires its version to be updated by editing
scripts/imgtool/__init__.py and modifying the exported version:
imgtool_version = "A.B.CrcN"
This version should match the current release number of MCUboot. The
rcN (with no dash) is accepted only for the pre-release versions
under test, while numbers are accepted only for the final releases.
For more information, see this link.
Mynewt release information
newt always fetches a versioned MCUboot release, so after
the RC step is finished, the release needs to be exported by modifying
repository.yml in the root directory; it must be updated with the
new release version, including updates to the pseudo keys
Zephyr release information
There is a version file used by Zephyr builds to indicate the version
of MCUboot being used which needs to be updated at
boot/zephyr/VERSION. For alignment with Zephyr versions, development
versions should set
whilst production versions should correctly set
PATCHLEVEL and clear
Tagging and release
To make a release, make sure your local repo is on the tip version by fetching from origin. Typically, the releaser should create a branch named after the particular release.
Create a commit on top of the branch that modifies the version number
in the top-level
README.md, and create a commit, with just this
change, with a commit text similar to “Bump to version a.b.c”.
Having the version bump helps to make the releases
easier to find, as each release has a commit associated with it, and
not just a tag pointing to another commit.
Once this is done, the release should create a signed tag with the appropriate tag name:
git tag -s va.b.c-rcn
The releaser will need to make sure that git is configured to use the proper signing key, and that the public key is signed by enough parties to be trusted.
At this point, the tag can be pushed to GitHub to make the actual release happen:
git push origin HEAD:refs/heads/main git push origin va.b.c-rcn
Branching after a release
After the final (non-
rc) a.b.0 release is made, a new branch must
be created and pushed:
git checkout va.b.c git checkout -b va.b-branch git push origin va.b-branch
This branch will be used to generate new incremental
for bug fixes or required minor updates (for example, new
Post release actions
Mark the MCUboot version as a development version.
The version number used should be specified for the next expected release. It should be larger than the last release version by incrementing the MAJOR or the MINOR number. It is not necessary to define the next version precisely as the next release version might still be different as it might be needed to do:
a patch release
a MINOR release while a MAJOR release was expected
a MAJOR release while a MINOR release was expected