 Ubuntu 16.04 LTS to Ubuntu 18.04 LTS and then to Ubuntu 20.04 LTS) are supported, while upgrades from non-LTS have only supported upgrade to the next release, regardless of its LTS status (e.g.Ubuntu 15.10 to Ubuntu 16.04 LTS).LTS releases have optional extended security maintenance (ESM) support available, including 14.04 "Trusty" that is otherwise out of public support, adding support for that version up to 2022.