Game Update 51 has been delayed, according to Bruce "Froech " Ferguson, Senior Producer, EverQuest II.  The highly anticipated game update, which now includes the Lavastorm zone revamp as well as the Fighter class revamp, was already postponed once in January.  Bruce said in his post on the official forums:

"I know many of you were expecting us to do so this week or next, but at this point, we just need some more time to spend working on it so that it's just right for all of you. Please be patient with us while we finish polishing the update, and as soon as we have a good date that we can ship out all of this exciting goodness, we'll let you know. "

Bruce also said this would delay the availability of the Beckett's magazine promotional item.  We have no word yet if Brewday is also delayed. 

source:  EQII Official Forums