Basically Vol 11 will have:
-Gym storage scene with Hyakurath
-Hot spring lesbian rape on Sylvia
-Grace going solo with Kizuna
-Hayuru being a shotacon
I'm sure the last one is the one most people are looking forward to the most.
The first three can take place at any point between Vol 8 and 10, but the last one definitely takes place after Reiri's install.