The update should only take the site down for an hour and a half this morning. During that time players won't be able to access their Initiates profile, but in theory when the site pops back up, everything should be fixed.
"This update should resolve the issues we've seen with some players being unable to accurately record their legacy experience (previous games played) to their Initiates profile," according to the update. "The update will also streamline how we synchronize your Initiates profile data, so you should notice a decrease in the amount of time synchronization takes.
"So, if you've been unable to get Arno's Legacy Costumes because you haven't received credit for prior AC titles, you should be able to starting tomorrow afternoon!"
The update, which is scheduled to run from 9 a.m. ET to 10:30 a.m. ET, won't detail the work being done to fix a slew of other issues with Unity, the team added. The folks working on Initiates are a completely separate team.