Recently, at the Open Source Summit Europe, it was announced that the period of long-term support for the Linux kernel (LTS) will be reduced, ArsTechnica reports. In 2017, the duration of LTS was increased from two years to six. However, after six years, the Linux community has found that it is very difficult to support software for such a long period of time. As a result, the kernel will return to a two-year LTS period.

The decision to return to the two-year period will not be immediate. The Linux community will continue to honor the existing end-of-life dates. This means that kernels 6.1, 5.15, 5.10, 5.4, 4.19, and 4.14 will still be supported for six years. However, future kernels will only be supported for two years. Initially, the six-year window was planned to be optional, but in practice, all kernels received this extended support period. This will no longer be the case in the future.

Jonathan Corbett, executive editor of Linux Weekly News, cited two main reasons for the decision. First, the old kernels have noticeably stopped being used, which led Corbett to note: “It doesn’t make sense to support [old kernels] for so long because people aren’t using them.” Second, a significant burden was placed on maintainers, many of whom are unpaid. They should have benefited from longer support from contributions from companies that use Linux, but this did not happen.

Implications for Android

A two-year support period may be acceptable for PCs, but it poses problems for Android. The initial extension to six years was designed primarily with Android and IoT devices in mind. On PCs, the two-year window simply reflects the time between kernel updates. However, for embedded devices that don’t update their kernel frequently, this two-year period covers most of the development cycle and the entire period of user support.

Back in 2017, Google emphasized that smartphone development typically takes two years, with the kernel being finalized at an early stage of the engineering process. This meant that by the time a smartphone was released, its LTS kernel was nearing the end of its life. As a result, consumers would be using outdated kernels for the entire lifetime of their devices.

The Android kernel development process is complex and involves several forks. First, Google forks a new version of Linux LTS to create the Android Common kernel. It is then sent to SoC vendors, such as Qualcomm, who create a fork for each SoC model. Subsequently, device manufacturers receive it and again make a fork for each device model.

Despite advances such as Google’s Generic Kernel Image (GKI) since 2017, major kernel updates for Android devices remain rare. For example, the Pixel 6, which was the first smartphone to feature GKI, came with Linux 5.10 and has remained on that version. This kernel is already three years old. Although Google hints at major updates to the GKI kernel in the future, no consumer device has yet received such an update. There are rumors that the upcoming Pixel 8 may introduce a longer support window, potentially paving the way for major kernel updates.