We’re happy to announce the first release of the new linux-raspberrypi-lts project developed by Togán Labs Ltd. This is a long-term support release of the Linux® kernel for use on Raspberry Pi platforms. This project aims to fill the gap left when the upstream support (centered on the official Raspberry Pi Linux repository at https://github.com/raspberrypi/linux) moves on to a new LTS kernel version. This has occurred recently with the upstream repository moving from the 4.4 kernel series to the 4.9 kernel series.



This is a Good Thing (TM) and is necessary to keep close to the mainline Linux kernel and to pull in new features – the last thing we want is an Evil Vendor Kernel which is never updated and forces downstream developers to backport required features themselves. However, this can leave behind users who aren’t able to move forward to the new kernel series immediately due to backwards compatibility worries, limited developer time or other concerns.



The 4.4 kernel series is unlikely to see any further updates in the official Raspberry Pi Linux repository. However, the linux-stable 4.4 kernel series continues to be maintained, with a current planned End of Life (EOL) of Feb 2018. Therefore it’s possible to pick up new 4.4 kernel releases from linux-stable and merge them into the linux-raspberrypi-lts 4.4 kernel branch for around the next 12 months. This should give most people who are using the 4.4 kernel series time to get their affairs in order and transition to the 4.9 kernel series.



Looking beyond Feb 2018, there is likely to be continued support for the 4.4 kernel series for several years as part of the the SLTS work (Super Long-Term Support) within the Civil Infrastructure Project (CIP). The current CIP plans call for maintenance of the 4.4 SLTS kernel series for at least 10 years from the date of the 4.4.0 release, taking us out into the mid-2020s. It should be possible to incorporate this work into the linux-raspberrypi-lts 4.4 branch if there is adequate interest in this.

Testing of linux-raspberrypi-lts releases will first focus on the basics – we’ll ensure that we can boot each release on all supported hardware devices and run a few commands manually after login. More substantial testing will be possible by arrangement with industry users – Togán Labs is able to provide test plans and detailed test results on a contract basis if needed. We’re also able to tailor test coverage to address exactly the features required for a particular industry application and ensure that these features continue to work as expected for the lifetime of the LTS kernel series.



For more information please see the full v4.4.53 release notes (https://www.toganlabs.com/downloads/linux-raspberrypi-lts/rpi-4.4.53/RELEASE_NOTES.txt) or contact Togán Labs directly at support@toganlabs.com.