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