S-corp Late Election, ATX efile, Form 2553

[G2R]

New client, new LLC in 2021.  They want to be taxed as an S-corp for 2021. They didn't file timely so I'm filing a late 2553. I found the button in ATX to add the verbiage to the top of 1120S (screenshot below for anyone looking for it). 

Question: do I attached a PDF of the signed 2553 to the efile or do I have to fax a copy to the IRS?  Should I do both? 

[mircpa]

You need attach a PDF of the signed 2553 to the efile