Our current version of Koji is 1.15.1. We should keep proceeding with the upgrade treadmill until we hit the latest version, to get bugfixes and support from upstream.
We need to upgrade our production Koji host (koji.chtc), our testing koji host (koji-hub-testing.chtc), and the new Koji host we're setting up (kojihub0000.chtc) in order to keep the databases in sync (since nine out of ten Koji versions come with a DB schema change).
koji.chtc and koji-hub-testing.chtc are both EL6 machines and the last Koji version to support EL6 is 1.17.0 so that's the version we'll be upgrading to for now. It also means that we'll be building the new versions of Koji in both 3.4 and devops, although there is no need to put them in a release.