New amended return (Form 1040-X) submission requirement.

For many years, people on this forum have been posting "Do not attach a corrected copy of Form 1040 to your amended return, just use Form 1040-X."

The IRS has updated the instructions for Form 1040-X to clarify this issue: https://www.irs.gov/instructions/i1040x#en_US_2026_publink1000166284

>New attachment requirement.

>For paper-filed Forms 1040-X, you must attach, to your completed Form 1040-X, a completed and updated Form 1040, 1040-SR, or 1040-NR, with your changes. See Assembling Your Return , later.