In this release we introduced 54 new rules and made modifications to 4 additional rules. The Sourcefire VRT has also added and modified multiple rules in the app-detect, blacklist, browser-ie, exploit-kit, file-flash, protocol-dns rule sets to provide coverage for emerging threats from these technologies. There were no changes made to the snort.conf in this release. In order to subscribe now to the VRT’s newest rule detection functionality, you can subscribe for as low as $29 US dollars a year for personal users.”]
Source: https://blog.snort.org/2014/04/sourcefire-vrt-certified-snort-rules_7339.html