As a user of an Ubuntu distro Xubuntu, I often wonder how long I can continue using version 16.04 LTS. End of life for 16.04 LTS is April 2021. Extended Security maintenance releases will continue through April 2024. So we have lots of years before that occurs. See below details by release from Ubuntu.
LTS or ‘Long Term Support’ releases are published every two years in April. LTS releases are the ‘enterprise grade’ releases of Ubuntu and are utilised the most. An estimated 95% of all Ubuntu installations are LTS releases, with more than 60% of large-scale production clouds running on the most popular OS images - Ubuntu 18.04, 16.04 and 14.04 LTS.
Every six months between LTS versions, Canonical publishes an interim release of Ubuntu, with18.10 being the latest example. These are production-quality releases and are supported for their lifespan, with sufficient time provided for users to update, but these releases do not receive the long-term commitment of LTS releases.
Interim releases will introduce new capabilities from Canonical and upstream open source projects, they serve as a proving ground for these new capabilities. Many developers run interim releases because they provide newer compilers or access to newer kernels and newer libraries, and they are often used inside rapid devops processes like CI/CD pipelines where the lifespan of an artifact is likely to be less than the support period of the interim release. Interim releases receive full security maintenance for ‘main’ during their lifespan.
Ubuntu kernel release cycle:
Canonical maintains multiple kernel packages for each LTS version of Ubuntu, which serve different purposes. Several of the kernel packages address the need for kernels with specific performance priorities, for example the low-latency kernel package. Others are focused on optimisation for a particular hypervisor, for example the kernel packages which are named after public clouds. You are recommended to use the detailed Ubuntu kernel guide to select the best Ubuntu kernel for your application.
In general, all of the LTS kernel packages will use the same base version of the Linux kernel, for example Ubuntu 18.04 LTS kernels typically used the 4.15 upstream Linux kernel as a base. Some cloud-specific kernels may use a newer version in order to benefit from improved mechanisms in performance or security that are material to that cloud. These kernels are all supported for the full life of their underlying LTS release.
In addition, the kernel versions from the subsequent four releases are made available on the latest LTS release of Ubuntu. So Ubuntu 16.04 LTS received the kernels from Ubuntu 16.10, 17.04, 17.10 and 18.04 LTS. These kernels use newer upstream versions and as a result offer an easy path to newer features and newer classes of hardware for many users of Ubuntu. Note however that these kernels ‘roll’ which means that they jump every six months until the next LTS. Large scale deployments that adopt these ‘hardware enablement’ or HWE kernels should manage those transitions explicitly. These newer HWE kernels are accompanied by a collection of userspace tools closely tied to the kernel and hardware, specifically X display enablement on newer graphics cards.
The Ubuntu kernel support lifecycle is as follows:
Source: https://www.ubuntu.com/about/release-cycle
