This is the latest stable version : 1.2.3
There is a known issue with Redmine 2.6.3 and Redmine 3.0.1. Don’t install these versions! Take a look here for more infos.
Support for Gitolite v2 will be drop in next stable branch ! (so actually 2.x, the current stable branch is 1.x). You’re strongly encouraged to migrate to Gitolite v3.