Ubuntu has two types of releases: standard and Long Term Support (or “LTS”). Standard updates are released every six months and receive security updates from Ubuntu for at least nine months, while LTS updates are released every two years and are supported for at least five years. This collection of guides will assist you in upgrading older Ubuntu LTS versions on any system, such as DigitalOcean droplets.
How To Upgrade to Ubuntu 22.04 Jammy Jellyfish
How To Upgrade to Ubuntu 20.04 Focal Fossa
How To Upgrade to Ubuntu 18.04 Bionic Beaver
How To Upgrade to Ubuntu 16.04 LTS
How to Upgrade Ubuntu 12.04 LTS to Ubuntu 14.04 LTS