The Rashoumon event will be re-run with a few changes. You can click here for a full translation of the event details courtesy of /u/taiboo of the /r/grandorder subreddit.
The biggest news here is being able to upgrade our servants via Fou cards to 2000 now. As such the guide will be updated to reflect that.
Another thing of note is this screenshot:
Looks like Kintoki will be getting an animation update. Hopefully it includes his NP.