[rules-users] Drools vs Guvnor vs Jira versioning

I'm a bit confused about the versioning of Drools and Guvnor. I downloaded Drools 5.1.1 Guvnor Standalone, but the 'About' window in the Guvnor Web UI says 5.0.0 SNAPSHOT 25673M, and the Issues tracker (Jira) on the community pages doesn't even list a 5.1.1 version when submitting a bug report. Can anyone clarify for me the relationship between Drools (Expert) and Drools Guvnor version numbers? Thanks, and obviously not terribly urgent. -Mike