The pre-order is over but it should be easily available sometime after the event.
As usual it’s more Kodomo and Otona series. They both aren’t rated R-18 so usual caveats apply. Oh and the images in the linked tweet aren’t the actual covers (also as usual).
Now I wrote it it’s already a twice-a-year thing with more or less same pattern every time. Including the barely-announced pre-order.