Will IRS mail sent to old address be received? I would think if you e-file 2017 that would update the address, so no need to wait for older paper returns to be processed. Given current backlog, you’re likely looking at much longer than 6-8 week processing time. In October, Rettig said IRS backlog was 5.3 million unopened pieces of mail, of which 2.5 million were paper returns. Although they are trying to prioritize return processing, you will still have at least a million returns in front of you.