For longtime users of Ubuntu Linux, it may feel like just yesterday that Ubuntu 11.04 “Natty Narwhal” first came out.

It's a particularly memorable release, of course, because it was the first desktop version of Canonical's popular Linux distribution to use the controversial Unity desktop by default.

Well, on Sunday, hard on the heels of the recent release of Ubuntu 12.10 “Quantal Quetzal,” Canonical announced that the relatively venerable Natty Narwhal has now reached its end of life.

Next up: Oneiric Ocelot

“The support period for Ubuntu 11.04 (Natty Narwhal) formally ends on October 28, 2012, and Ubuntu Security Notices no longer includes information or updated packages for Ubuntu 11.04,” wrote Ubuntu Release Manager Kate Stewart in the official announcement on Sunday.

Users of Ubuntu 11.04 should now upgrade, but they need to do it in stepwise fashion, Stewart noted, beginning with a move to Ubuntu 11.10 “Oneiric Ocelot.” Instructions for that first upgrade are available on the Ubuntu site.

Both Ubuntu 11.10 and Ubuntu 12.04 “Precise Pangolin”--the next step along the way--are still actively supported with security updates and select high-impact bug fixes, Stewart said. Ubuntu 12.04, moreover, is a Long Term Support release as well, making it particularly attractive for business users.

A world of choice

Then, too, of course, there's the newly launched Quantal Quetzal, which incorporates a raft of new features including full-disk encryption and a revamped update manager as well as the integration of online search and Web apps.

Outside the Ubuntu realm, meanwhile, there's a whole world of other Linux distributions that are free for you to test and try out at will.

The bottom line, though, is that if you're still on Natty Narwhal, it's time to find something new. Fortunately for you, in the world of Linux, there's never any shortage of choice.