This is the documentation for the latest (master) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

Development Model


  • mainline: The main tree where the core functionality and core features are being developed.

  • subsystem/feature branch: is a branch within the same repository. In our case, we will use the term branch also when referencing branches not in the same repository, which are a copy of a repository sharing the same history.

  • upstream: A parent branch the source code is based on. This is the branch you pull from and push to, basically your upstream.

  • LTS: Long Term Support