Entry of Invoice of fy 2017-18 in gstr 1 now

Mr.X has filed GSTR3B and GSTR1 for FY 2017-18 but 1 invoice for which tax was deposited via 3B but could not be shown in GSTR 1 so the buyer is not able to see the same in his GSTR2A.

Plz suggest, whether now this invoice can be updated in current years GSTR 1 or any other option with which buyer can avail ITC and invoice can be made visible in GSTR2A of buyer.

Thanks