Version 1.6 is a comprehensive upgrade, that includes new reference-data from the SitePoint Reference. The support tables now show information for Google Chrome, and the latest versions of Firefox, Safari, Opera and IE.
This version also adds at-rules to special search (when looking-up a selected element from the HTML panel), and includes a number of smaller enhancements to the user-interface.
And finally, Firebug support itself has been extended to Firebug 1.7.0, and browser support to Firefox 4.0.x and Flock 2.6.x.
See complete version history