Linux Yocto

==Release Cadence==
Each release of the Yocto Project, roughly every six months, includes one or more versions of the Linux kernel with a broad range of hardware support. While tooling is provided to use any Linux kernel you wish, the linux-yocto Linux kernel recipes are tested with all the emulated targets, the core hardware BSPs, and some vendor layers.
The LTSI is a Linux Foundation project that saw its first LTSI kernel released in 2011. The latest LTSI release was 4.14.75-ltsi, released in 2018. The work of the LTSI appears to have been taken over by another LF project: the Civil Infrastructure Project (CIP). The Linux kernel maintainers also maintain their own LTS kernels. Historically the Yocto Project tried to provide an LTSI plus a recent kernel.org kernel with each release. More recently the project works to provide at least a kernel.org LTS kernel plus a more recent kernel.org kernel.
The final selection of which versions to ship in any release is made approximately two weeks prior to the feature freeze date for the release.
==Prior Releases==
Yocto Project Release	LTSI Kernel Version	LTS Kernel Version 	Released Kernel Version
Yocto Project 4.1 	 	linux-yocto_5.15 	linux-yocto_5.19
Yocto Project 4.0 	 	linux-yocto_5.10linux-yocto_5.15	
Yocto Project 3.4 	 	linux-yocto_5.10 	linux-yocto_5.14
Yocto Project 3.3 	 	linux-yocto_5.4linux-yocto_5.10 	
Yocto Project 3.2 	 	linux-yocto_5.4 	linux-yocto_5.8
Yocto Project 3.1 	 	linux-yocto_5.4 	
Yocto Project 3.0 	 	linux-yocto_4.19 	linux-yocto_5.2
Yocto Project 2.7 	 	linux-yocto_4.19 	linux-yocto_5.0
Yocto Project 2.6 	linux-yocto_4.9 	linux-yocto_4.14 	linux-yocto_4.18
Yocto Project 2.5 	linux-yocto_4.9 	linux-yocto_4.14 	linux-yocto_4.15
Yocto Project 2.4 	linux-yocto_4.9 	linux-yocto_4.9 	linux-yocto_4.12
Yocto Project 2.3 	linux-yocto_4.1 	linux-yocto_4.9 	linux-yocto_4.10
Yocto Project 2.2 	linux-yocto_4.1 	linux-yocto_4.4 	linux-yocto_4.8
Yocto Project 2.1 	linux-yocto_4.1 	linux-yocto_4.1 	linux-yocto_4.4
Yocto Project 2.0 	linux-yocto_3.14 	linux-yocto_3.14 	linux-yocto_4.1
Yocto Project 1.8 	linux-yocto_3.14 	linux-yocto_3.14 	linux-yocto_3.19
Yocto Project 1.7 	linux-yocto_3.10 	linux-yocto_3.14 	linux-yocto_3.17
Yocto Project 1.6 	linux-yocto_3.10 	linux-yocto_3.10 	linux-yocto_3.14
Yocto Project 1.5 	linux-yocto_3.4 	linux-yocto_3.4 	linux-yocto_3.10
Yocto Project 1.4 	linux-yocto_3.4 	linux-yocto_3.4 	linux-yocto_3.8
Yocto Project 1.3 	linux-yocto_3.0 	linux-yocto_3.2 	linux-yocto_3.4
Yocto Project 1.2 	linux-yocto_3.0 	linux-yocto_3.0 	linux-yocto_3.2
Yocto Project 1.1 	linux-yocto_2.6 	linux-yocto_2.6 	linux-yocto_3.0
Yocto Project 1.0 	 	 	linux-yocto_2.6
==Version Lifecycle / Support==
While we make every effort to select a longterm Linux kernel for each new release kernel, occasionally our releases do not align with those of the Linux kernel, as was the case with the Yocto Project 1.4 release and the 3.8 kernel. In these cases, the non-longterm kernel version will be dropped in the subsequent release, rather than becoming the next LTSI kernel. This can be seen in the 1.5 release where 3.8 was effectively dropped, 3.4 remained as the LTSI kernel, and 3.10 was added as the new release kernel.
In terms of support, the linux-yocto recipes are treated the same as all the other recipes in a given release. They are supported for the life of that release [3] and the corresponding stable updates [4].
==FAQ==
*Q: Why don't you support an LTSI kernel across new Yocto Project releases for as long as the that LTSI kernel is supported by the LTSI project?
**A: A new LTSI kernel is selected once per year and supported for two years. This allows for multiple active LTSI kernels at any point in time. It would be infeasible purely from a support and QA perspective to support all of them in every release of the Yocto Project. Furthermore, the LTSI kernel is targeted at productization teams that want to minimize change across the life of their product. It stands to reason if the kernel version must remain static, then so should the OS stack on top of it. For these reasons, LTSI kernel versions are supported for the life of the release they originally ship with.
==References==
# Long Term Support Kernel Schedule
# LTSI Development Guide
# Yocto Project Releases
# Yocto Project Stable Branch Maintenance