Ubuntu Linux logo
Ubuntu Linux is the most popular desktop Linux distribution today, based on Debian Linux. Another popular distro – Linux Mint – is based on Ubuntu.
Current release as of April 2021: Ubuntu Linux 21.04 - Hirsute Hippo.
Ubuntu gets a long-term release every 2 years in April. These builds receive the .04 minor version number: 19.04, 20.04 etc
This is the timeline of recent Ubuntu Release cycles, taken from the official Ubuntu Release Cycles page:
Ubuntu Release Cycles (image credit goes to Ubuntu.com)
Each Ubuntu Linux release receives a codename: