| Active kernel releases |
| ====================== |
| |
| :slug: releases |
| :category: Releases |
| |
| There are several main categories into which kernel releases may fall: |
| |
| Prepatch |
| Prepatch or "RC" kernels are mainline kernel pre-releases that are |
| mostly aimed at other kernel developers and Linux enthusiasts. They |
| must be compiled from source and usually contain new features that |
| must be tested before they can be put into a stable release. |
| Prepatch kernels are maintained and released by Linus Torvalds. |
| |
| Mainline |
| Mainline tree is maintained by Linus Torvalds. It's the tree where |
| all new features are introduced and where all the exciting new |
| development happens. New mainline kernels are released every 9-10 |
| weeks. |
| |
| Stable |
| After each mainline kernel is released, it is considered "stable." |
| Any bug fixes for a stable kernel are backported from the mainline |
| tree and applied by a designated stable kernel maintainer. There are |
| usually only a few bugfix kernel releases until next mainline kernel |
| becomes available -- unless it is designated a "longterm maintenance |
| kernel." Stable kernel updates are released on as-needed basis, |
| usually once a week. |
| |
| Longterm |
| There are usually several "longterm maintenance" kernel releases |
| provided for the purposes of backporting bugfixes for older kernel |
| trees. Only important bugfixes are applied to such kernels and they |
| don't usually see very frequent releases, especially for older |
| trees. |
| |
| .. table:: Longterm release kernels |
| |
| ======== ================================ ============ ================== |
| Version Maintainer Released Projected EOL |
| ======== ================================ ============ ================== |
| 6.6 Greg Kroah-Hartman & Sasha Levin 2023-10-29 Dec, 2026 |
| 6.1 Greg Kroah-Hartman & Sasha Levin 2022-12-11 Dec, 2026 |
| 5.15 Greg Kroah-Hartman & Sasha Levin 2021-10-31 Dec, 2026 |
| 5.10 Greg Kroah-Hartman & Sasha Levin 2020-12-13 Dec, 2026 |
| 5.4 Greg Kroah-Hartman & Sasha Levin 2019-11-24 Dec, 2025 |
| 4.19 Greg Kroah-Hartman & Sasha Levin 2018-10-22 Dec, 2024 |
| ======== ================================ ============ ================== |
| |
| Distribution kernels |
| -------------------- |
| Many Linux distributions provide their own "longterm maintenance" |
| kernels that may or may not be based on those maintained by kernel |
| developers. These kernel releases are not hosted at kernel.org and |
| kernel developers can provide no support for them. |
| |
| It is easy to tell if you are running a distribution kernel. Unless you |
| downloaded, compiled and installed your own version of kernel from |
| kernel.org, you are running a distribution kernel. To find out the |
| version of your kernel, run `uname -r`:: |
| |
| # uname -r |
| 5.6.19-300.fc32.x86_64 |
| |
| If you see anything at all after the dash, you are running a distribution |
| kernel. Please use the support channels offered by your distribution |
| vendor to obtain kernel support. |
| |
| Releases FAQ |
| ------------ |
| Here are some questions we routinely receive about kernel release |
| versions. See also the main "FAQ" section for some other topics. |
| |
| When is the next mainline kernel version going to be released? |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| Linux kernel follows a simple release cadence: |
| |
| - after each mainline release, there is a 2-week "merge window" period |
| during which new major features are introduced into the kernel |
| - after the merge window closes, there is a 7-week bugfix and |
| stabilization period with weekly "release candidate" snapshots |
| - rc7 is usually the last release candidate, though occasionally there |
| may be additional rc8+ releases if that is deemed necessary |
| |
| So, to find the approximate date of the next mainline kernel release, |
| take the date of the previous mainline release and add 9-10 weeks. |
| |
| What is the next longterm release going to be? |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| Longterm kernels are picked based on various factors -- major new |
| features, popular commercial distribution needs, device manufacturer |
| demand, maintainer workload and availability, etc. You can roughly |
| estimate when the new longterm version will become available based on |
| how much time has elapsed since the last longterm version was chosen. |
| |
| Why are some longterm versions supported longer than others? |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| The "projected EOL" dates are not set in stone. Each new longterm kernel |
| usually starts with only a 2-year projected EOL that can be extended |
| further if there is enough interest from the industry at large to help |
| support it for a longer period of time. |
| |
| Does the major version number (4.x vs 5.x) mean anything? |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| No. The major version number is incremented when the number after the |
| dot starts looking "too big." There is literally no other reason. |
| |
| Does the odd-even number still mean anything? |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| A long time ago Linux used a system where odd numbers after the first |
| dot indicated pre-release, development kernels (e.g. 2.1, 2.3, 2.5). |
| This scheme was abandoned after the release of kernel 2.6 and these days |
| pre-release kernels are indicated with "-rc". |
