Event 4 - 90's - Entry Deadline

Would somebody please remind me what the deadline will be for getting our 90's teams in the assigned leagues?

I know league assignments have not been made yet, but I want to make sure I have the deadline in mind. My plan will be to start organizing my 90's team well in advance of the deadline.

Event 4's deadline will be Thursday March 30. This is the 90's mystery card set Event.