14.04
Starting with the Ubuntu Server 14.10 release, newer releases of OpenStack are available via Cloud archive for the Ubuntu Server 14.04 LTS release. Juno and Liberty were supported for 18 months each, and Kilo was supported for 36 months. Mitaka, 16.04's OpenStack version, is supported in the Cloud Archive for 3 years, i.e. until the end of the Ubuntu 14.04 LTS lifecycle.
16.04
Starting with the Ubuntu Server 16.10 release, newer releases of OpenStack are available via Cloud archive for the Ubuntu Server 16.04 LTS release. Newton and Pike will be supported for 18 months each, and Ocata for 36 months. Queens, 18.04's OpenStack version, is supported in the Cloud Archive for 3 years, i.e. until the end of the Ubuntu 16.04 LTS lifecycle.
18.04
Starting with the Ubuntu Server 18.10 release, newer releases of OpenStack will be available via Cloud archive for the Ubuntu Server 18.04 LTS release. Rocky and Stein will be supported for 18 months each, and T for 36 months. When 20.04's OpenStack version is released that will be added to the Cloud Archive with support for 3 years, i.e. until the end of the Ubuntu 18.04 LTS lifecycle.
