Timeline

Cosmic (18.10) Active Development
Successor to Ubuntu Bionic (18.04)
Milestones:

Ubuntu 18.10

Bionic (18.04) Active Development
Successor to Ubuntu Artful (17.10)
Milestones:

Ubuntu 18.04

Artful (17.10) Current Stable Release
Successor to Ubuntu Zesty (17.04)
Milestones:

Ubuntu 17.10

Zesty (17.04) Supported
Successor to Ubuntu Yakkety (16.10)
Milestones:

Ubuntu 17.04

Yakkety (16.10) Supported
Successor to Ubuntu Xenial (16.04)
Milestones:

Ubuntu 16.10

Xenial (16.04) Current Stable Release
Successor to Ubuntu Wily (15.10)
Milestones:

Ubuntu 16.04

Wily (15.10) Supported
Successor to Ubuntu Vivid (15.04)
Milestones:

Ubuntu 15.10

Vivid (15.04) Supported
Successor to Ubuntu Utopic (14.10)
Milestones:

Ubuntu 15.04

Utopic (14.10) Supported
Successor to Ubuntu Trusty (14.04)
Milestones:

Ubuntu 14.10

Trusty (14.04) Supported
Successor to Ubuntu Saucy (13.10)
Milestones:

Ubuntu 14.04

Saucy (13.10) Supported
Successor to Ubuntu Raring (13.04)
Milestones:

Ubuntu 13.10

Raring (13.04) Supported
Successor to Ubuntu Quantal (12.10)
Milestones:

Ubuntu 13.04

Quantal (12.10) Supported
Successor to Ubuntu Precise (12.04)
Milestones:

Ubuntu 12.10

Precise (12.04) Supported
Successor to Ubuntu Oneiric (11.10)
Milestones:

Ubuntu 12.04

Oneiric (11.10) Supported
Successor to Ubuntu Natty (11.04)
Milestones:

Ubuntu 11.10

Natty (11.04) Supported
Successor to Ubuntu Maverick (10.10)
Milestones:

Ubuntu 11.04

Bullseye (11.0) Active Development
Successor to Ubuntu Buster (10.0)
Milestones:

Debian Bullseye

Maverick (10.10) Supported
Successor to Ubuntu Lucid (10.04)
Milestones:

Ubuntu 10.10 is good.

Lucid (10.04) Supported
Successor to Ubuntu Karmic (9.10)
Milestones:

Ubuntu 10.04 is good.

Buster (10.0) Active Development
Successor to Ubuntu Stretch (9.0)
Milestones:

Debian 10.0

Karmic (9.10) Supported
Successor to Ubuntu Jaunty (9.04)
Milestones:

Ubuntu 9.10 is good.

Jaunty (9.04) Supported
Successor to Ubuntu Intrepid (8.10)
Milestones:

Ubuntu 9.04 is good.

Stretch (9.0) Current Stable Release
Successor to Ubuntu Jessie (8.0)
Milestones:

Debian 9.0

Intrepid (8.10) Supported
Successor to Ubuntu Hardy (8.04)
Milestones:

Ubuntu 8.10 is good.

Hardy (8.04) Supported
Successor to Ubuntu Gutsy (7.10)
Milestones:

Ubuntu 8.04 is good.

Raspbian Jessie (8.0) Supported
Successor to Ubuntu Raspbian Wheezy (7.0)
Milestones:

Raspbian Jessie

Jessie (8.0) Supported
Successor to Ubuntu Wheezy (7.0)
Milestones:

Debian 8.0 Jessie

Gutsy (7.10) Obsolete
Successor to Ubuntu Feisty (7.04)
Milestones:

Ubuntu 7.10 is good.

Feisty (7.04) Obsolete
Successor to Ubuntu Edgy (6.10)
Milestones:

Ubuntu 7.04 is good.

Raspbian Wheezy (7.0) Supported
Successor to Ubuntu Wheezy (7.0)
Milestones:

Raspbian 7.0 Wheezy

Wheezy (7.0) Supported
Successor to Ubuntu Lucid (10.04)
Milestones:

Debian 7.0 Wheezy

Edgy (6.10) Obsolete
Successor to Ubuntu Dapper (6.06)
Milestones:

Ubuntu 6.10 is good.

Dapper (6.06) Obsolete
Successor to Ubuntu Breezy (5.10)
Milestones:

Ubuntu 6.06 is good.

Squeeze (6.0) Supported
Successor to Ubuntu Lucid (10.04)
Milestones:

Debian 6.0 Squeeze

Breezy (5.10) Obsolete
Successor to Ubuntu Hoary (5.04)
Milestones:

Ubuntu 5.10 is good.

Lenny (5.04) Supported
Successor to Ubuntu Lucid (10.04)
Milestones:

Debian 5.04 is stable.

Hoary (5.04) Obsolete
Successor to Ubuntu Warty (4.10)
Milestones:

Ubuntu 5.04 is good.

Warty (4.10) Obsolete
Milestones:

Ubuntu 4.10 is good.