This article documents the version history of the Linux kernel. The Linux kernel is a free and open-source, monolithic, Unix-like operating system kernel. It was conceived and created in 1991 by Linus Torvalds. Linux kernels have different support levels depending on the version. The oldest currently-supported version, 4.9, released in December 2016, was declared to have six years of Long-Term Support (LTS), followed by Super-Long-Term Support (SLTS), i.e. Civil Infrastructure Platform will provide support (for 32-bit ARM and x86-64 only) until at least 2026, possibly until 2036.