1.. _zephyr_release_notes: 2 3Releases 4######## 5 6Zephyr project is provided as source code and build scripts for different target 7architectures and configurations, and not as a binary image. Updated versions of 8the Zephyr project are released approximately every four months. 9 10All Zephyr project source code is maintained in a `GitHub repository`_. In order 11to use a released version of the Zephyr project, it is recommended that you use 12:ref:`west` to :ref:`get_the_code` of the release you are interested in. 13 14The technical documentation for current and past releases is available at 15https://docs.zephyrproject.org/ (use the version selector to select your release 16of interest). 17 18Release Life Cycle and Maintenance 19********************************** 20 21Periodic Releases 22================= 23 24The Zephyr project provides periodic releases every 4 months leading to the 25long term support releases approximately every 2 years. Periodic and non-LTS 26releases are maintained with updates, bug fixes and security related updates 27for at least two cycles, meaning that the project supports the most recent two 28releases in addition to the most recent LTS. 29 30Long Term Support and Maintenance 31================================= 32 33A Zephyr :ref:`Long Term Support (LTS) <release_process_lts>` release is 34published every 2 years and is branched and maintained independently from the 35main tree for at least 2.5 years after it was released. 36 37Support and maintenance for an LTS release stops at least half a year 38after the following LTS release is published. 39 40Security Fixes 41============== 42 43Each security issue fixed within Zephyr is backported or submitted to the 44following releases: 45 46- Currently supported Long Term Support (LTS) release. 47 48- The most recent two releases. 49 50For more information, see :ref:`Security Vulnerability Reporting <reporting>`. 51 52 53Supported Releases 54****************** 55 56+-----------------+----------------+---------------+ 57| Release | Release date | EOL | 58+=================+================+===============+ 59| `Zephyr 2.7.5`_ | 2023-06-01 | 2024-08-31 | 60+-----------------+----------------+---------------+ 61| `Zephyr 3.6.0`_ | 2024-02-23 | 2024-11-29 | 62+-----------------+----------------+---------------+ 63| `Zephyr 3.5.0`_ | 2023-10-20 | 2024-07-26 | 64+-----------------+----------------+---------------+ 65 66As of 2022-01-01, LTS1 (1.14.x) is not supported and has reached end of life (EOL). 67 68Release Notes 69************* 70 71Release notes contain a list of changes that have been made to the different 72areas of the project during the development cycle of the release. 73Changes that require the user to modify their own application to support the new 74release may be mentioned in the release notes, but the details regarding `what` 75needs to be changed are to be detailed in the release's migration guide. 76 77.. toctree:: 78 :maxdepth: 1 79 :glob: 80 :reversed: 81 82 eol_releases 83 release-notes-2.7 84 release-notes-3.[5-6] 85 86Migration Guides 87**************** 88 89Zephyr provides migration guides for all major releases, in order to assist 90users transition from the previous release. 91 92As mentioned in the previous section, changes in the code that require an action 93(i.e. a modification of the source code or configuration files) on the part of 94the user in order to keep the existing behavior of their application belong in 95in the migration guide. This includes: 96 97- Breaking API changes 98- Deprecations 99- Devicetree or Kconfig changes that affect the user (changes to defaults, 100 renames, etc) 101- Treewide changes that have an effect (e.g. changing the include path or 102 defaulting to a different C standard library) 103- Anything else that can affect the compilation or runtime behavior of an 104 existing application 105 106.. toctree:: 107 :maxdepth: 1 108 :glob: 109 :reversed: 110 111 migration-guide-* 112 113.. _`GitHub repository`: https://github.com/zephyrproject-rtos/zephyr 114.. _`GitHub tagged releases`: https://github.com/zephyrproject-rtos/zephyr/tags 115.. _`Zephyr 2.7.5`: https://docs.zephyrproject.org/2.7.5/ 116.. _`Zephyr 3.5.0`: https://docs.zephyrproject.org/3.5.0/ 117.. _`Zephyr 3.6.0`: https://docs.zephyrproject.org/3.6.0/ 118