This Friday, December 8th is the Community Testing Day for Firefox 15.0.9/220.127.116.11 along with Thunderbird 18.104.22.168/2.0b1. Also Firefox 22.214.171.124 RC1 is now on the nightlies directory. I noticed today my ‘about screen’ no longer shows as Bon Echo 126.96.36.199 Pre, just Bon Echo 188.8.131.52
The estimated release date for Firefox 184.108.40.206/220.127.116.11 (this may also include Thunderbird 18.104.22.168/2.0b1 builds as well) is Thursday, December 14th. Keep in mind this date is not set in stone and could likely change depending on the outcome of Friday’s testing day.
News Source: mozillaZine Forums Firefox Builds