Stableperl is a fork, or a branch, of the official perl with the goal of providing stability and compatibility. See stableperl.schmorp.de for details.
You can also look at the Canary::Stability and Stableperl FAQ, and you can download releases at http://stableperl.schmorp.de/dist/.
Contact for this page: Marc Lehmann <schmorpforge@schmorp.de>.