If your DD is expired, They will still give you AOR and ask you to submit a new payment with a new DD. Once you Courier them the new DD they will return your DD to the mailing address that you confirm on the AOR mail.
It has come to notice that recently they have sent the package back asking for new payments which was not observed before. Normally they ask for new DD in the AOR, but OINP keeps changing their strategy all the time. One side they say they will not accept any applications for re submission and other side they return the package and ask to re submit in 30 days.