My Japanese isn`t that great but the general gist of last confidential the staff posted is

1: This is the last update on March 8 before the service ends (I assume there`ll be minor ones incase of errors and bugs though), 2: one last event, a new boss for it too, Land Battleship Ratte and finally 3: nothing to say on the art book at this time.

Seemed to be no mention of any new himes or new satoru promotions as far as I can tell and there was some information about the event but I don`t understand most of it.