MD set out an alert on this.  It says "soon".  Hope that narrows it down for you.  Actually, now we know why MD extended to 07/15 versus the 05/17.

Having gone through the new PTE stuff with resident, nonresident, and a combo of both I can tell you it's a nightmare so I understand why the Comptroller's office needs to time to figure this new law out.

There will also be a way to reverse your election if payments were already made on the PTE.