The DDO devs are being cagey about it, with the best answer so far being "Really really really incredibly soon." The exact time may be a secret, but when this update does arrive, it will bring some bonuses that players should enjoy. There will be a 10% XP bonus for quests and a 30% bonus to guild renown through August 29th.
Update 6 will be available to VIPs sometime today, and available to all other players in the DDO Store Thursday at a cost of 450 Turbine Points.
[Update: Update 6 is now live]