This update was the perfect time to release a /facepalm animation for Anarchy Online . Most of the team is slowly recovering from being awake for almost 48 hours straight.

There were a great many Anarchy Credits in the update that we thought might destroy the universe.

A new client RDB for everyone that allows us to add more files and process faster.
Instanced cities for everyone.
Instancing Pandemonium.
Instanced playfields finally being displayed with the correct lighting and effects they were always meant to have.
Messing with the City Advantages code.
New apartments accessed in a new way.
New Hostile Target nano window....

Any of these could have done it...as easily in the past it could have been the social window...the mechs...the battlestations...or the raid system...or the new instancing system itself. So many opportunities to break the entire game...and force the rollback we have managed to avoid for about 6 years..since 12.6.

What actually did it?

The new system for cool-downs for nanos. In the past if we wanted an action to be unavailable for use (beyond the recharge/global cooldown of everything) we were forced to depend on silly blocker nanos..."You can not cast this while XXXXX is running." The new cooldowns meant we could dispense with the silly blocker nanos and properly display (on the shortcut bar even!) the amount of time until these actions were available again. This is where things went "bad".

"Crashing" or exiting the game very rapidly would break these cooldowns and corrupt your character information. Anything contained in your character after this cooldown information was corrupted...this resulted in your research and perks effectively vanishing. Importantly your "Save" position also became corrupt...anyone who died in this state would then crash the entire server...not surprisingly breaking other characters on the same server who were also in this cooldown state. One broken character would then create more crashes...then more broken characters as a result...and from there it began to spread across all dimensions like a virus.

Doctors had the longest cooldown of this kind in common use...so they were immediately the first players who were susceptible to this issue...and in the end what allowed us to locate the problem and eliminate it in the update we released at 5am on Thursday.