This Friday, December 8th is the Community Testing Day for Firefox 15.0.9/184.108.40.206 along with Thunderbird 220.127.116.11/2.0b1. Also Firefox 18.104.22.168 RC1 is now on the nightlies directory. I noticed today my ‘about screen’ no longer shows as Bon Echo 22.214.171.124 Pre, just Bon Echo 126.96.36.199
The estimated release date for Firefox 188.8.131.52/184.108.40.206 (this may also include Thunderbird 220.127.116.11/2.0b1 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