The full history of releases can be found on the GitHub repository `Releases page`_. There you can find release notes, links to each version of the documentation, and instructions for obtaining each version.
Another place to find documentation for all releases is the documentation page, where you can go to the bottom-left corner and click the versions dropup (a bar with a small triangle). You can also use this dropup to switch between versions of the documentation.
- For production purposes, use the `current stable version`_. Stable versions have been manually tested, and are updated with "bugfix releases" which fix bugs without changing other functionality (see `Versioning Scheme`_ for more details).
In order to maximize the time between updates to new ESP-IDF versions, use the latest stable Long Term Support release version. This version can be found on the `Releases page`_.
- For prototyping, experimentation or for developing new ESP-IDF features, use the `latest version (master branch in Git) <https://docs.espressif.com/projects/esp-idf/en/latest/>`_. The latest version in the master branch has all the latest features and has passed automated testing, but has not been completely manually tested ("bleeding edge").
- If a required feature is not yet available in a stable release, but you do not want to use the master branch, it is possible to check out a pre-release version or a release branch. It is recommended to start from a stable version and then follow the instructions for :ref:`updating-pre-release` or :ref:`updating-release-branch`.
- Major Releases, like ``v3.0``, add new functionality and may change functionality. This includes removing deprecated functionality.
If updating to a new major release (for example, from ``v2.1`` to ``v3.0``), some of your project's code may need updating and functionality may need to be re-tested. The release notes on the `Releases page`_ include lists of Breaking Changes to refer to.
- Minor Releases like ``v3.1`` add new functionality and fix bugs but will not change or remove documented functionality, or make incompatible changes to public APIs.
If updating to a new minor release (for example, from ``v3.0`` to ``v3.1``), your project's code does not require updating, but you should re-test your project. Pay particular attention to the items mentioned in the release notes on the `Releases page`_.
If updating to a new bugfix release (for example, from ``v3.0`` to ``v3.0.1``), you do not need to change any code in your project, and you only need to re-test the functionality directly related to bugs listed in the release notes on the `Releases page`_.
Each ESP-IDF major and minor release version has an associated support period. After this period, the release is End of Life and no longer supported. Some releases are designated Long Term Support, which means the support period is longer than for other releases.
The `ESP-IDF Support Period Policy`_ explains this in detail, and describes how the support periods for each release are determined.
Each release on the `Releases page`_ includes information about the support period for that particular release.
As a general guideline:
- Using Long Term Support releases will maximize the amount of time between required ESP-IDF major or minor upgrades.
- Using standard stable releases will require more frequent upgrades to new ESP-IDF versions. However, this means that new features and major improvements will be available more frequently.
It is also possible to upgrade from a Long Term Support release to a standard release, and vice versa.
The ESP-IDF version is also compiled into the firmware and can be accessed (as a string) via the macro ``IDF_VER``. The default ESP-IDF bootloader will print the version on boot (the version information is not always updated in code, it only changes if that particular source file is recompiled).
If writing code that needs to support multiple ESP-IDF versions, the version can be checked at compile time using :ref:`compile-time macros<idf-version-h>`.
- New work is always added on the master branch (latest version) first. The ESP-IDF version on ``master`` is always tagged with ``-dev`` (for "in development"), for example ``v3.1-dev``.
- When a new version (developed on ``master``) becomes feature complete and "beta" quality, a new branch is made for the release, for example ``release/v3.1``. A pre-release tag is also created, for example ``v3.1-beta1``. You can see a full `list of branches`_ and a `list of tags`_ on GitHub. Beta pre-releases have release notes which may include a significant number of Known Issues.
- As testing of the beta version progresses, bug fixes will be added to both the ``master`` branch and the release branch. New features for the next release may start being added to ``master`` at the same time.
- Once testing is nearly complete a new release candidate is tagged on the release branch, for example ``v3.1-rc1``. This is still a pre-release version.
- If no more significant bugs are found or reported, then the final Major or Minor Version is tagged, for example ``v3.1``. This version appears on the `Releases page`_.
- As bugs are reported in released versions, the fixes will continue to be committed to the same release branch.
- Regular bugfix releases are made from the same release branch. After manual testing is complete, a bugfix release is tagged (i.e. ``v3.1.1``) and appears on the `Releases page`_.
-:ref:`updating-master` is recommended for the latest features, development use, and testing.
-:ref:`updating-release-branch` is a compromise between the first two.
..note:: These guides assume that you already have a local copy of ESP-IDF cloned. To get one, check Step 2 in the :doc:`Getting Started </get-started/index>` guide for any ESP-IDF version.
- When a bugfix release for the version you are using is released (for example, if using ``v3.0.1`` and ``v3.0.2`` is released), check out the new bugfix version into the existing ESP-IDF directory:
- When major or minor updates are released, check the Release Notes on the releases page and decide if you want to update or to stay with your current release. Updating is via the same Git commands shown above.
..note:: If you installed the stable release via zip file instead of using git, it might not be possible to update versions using the commands. In this case, update by downloading a new zip file and replacing the entire ``IDF_PATH`` directory with its contents.
It is also possible to ``git checkout`` a tag corresponding to a pre-release version or release candidate, the process is the same as :ref:`updating-stable-releases`.
Pre-release tags are not always found on the `Releases page`_. Consult the `list of tags`_ on GitHub for a full list. Caveats for using a pre-release are similar to :ref:`updating-release-branch`.
.._`updating-master`:
Updating to Master Branch
^^^^^^^^^^^^^^^^^^^^^^^^^
..note:: Using Master branch means living "on the bleeding edge" with the latest ESP-IDF code.
To use the latest version on the ESP-IDF master branch, this is the process to follow:
- Periodically, re-run ``git pull`` to pull the latest version of master. Note that you may need to change your project or report bugs after updating your master branch.
- To switch from master to a release branch or stable version, run ``git checkout`` as shown in the other sections.
..important:: It is strongly recommended to regularly run ``git pull`` and then ``git submodule update --init --recursive`` so a local copy of master does not get too old. Arbitrary old master branch revisions are effectively unsupportable "snapshots" that may have undocumented bugs. For a semi-stable version, try :ref:`updating-release-branch` instead.
In terms of stability, using a release branch is part-way between using the master branch and only using stable releases. A release branch is always beta quality or better, and receives bug fixes before they appear in each stable release.
..note:: There is no dedicated documentation for release branches. It is recommended to use the documentation for the closest version to the branch which is currently checked out.
