Tax Year 2026 Form 1040 series and extensions Modernized e-File (MeF) Assurance Testing System (ATS) information

Tax year 2026, Form 1040 Modernized e-File (MeF) Assurance Testing System (ATS) information is outlined below. If you support these forms, you will need to contact the e-Help Desk for testing. Please monitor this page for any tax year 2026, Form 1040 series and extensions ATS scenario updates.

ATS opens on October 13, 2026

Tax year 2026 Form 1040 series and extensions MeF ATS scenarios

• 1040 MeF ATS scenario 1 PDF (Form 1040) 
• 1040 MeF ATS scenario 2 PDF (Form 1040)
• 1040 MeF ATS scenario 3 PDF (Form 1040) 
• 1040 MeF ATS scenario 4 PDF (Form 1040)
• 1040 MeF ATS scenario 5 PDF (Form 1040)
• 1040 MeF ATS scenario 6 PDF (Form 1040)
• 1040 MeF ATS scenario 7 PDF (Form 4868)
• 1040 MeF ATS scenario 8 PDF(Form 1040-SS) 
• 1040 MeF ATS scenario 9 PDF (Form 1040-SS)
• 1040 MeF ATS scenario 1 PDF (Form 1040-NR) 
• 1040 MeF ATS scenario 2 PDF (Form 1040-NR)
• 1040 MeF ATS scenario 3 PDF (Form 1040-NR)

Note: These are draft scenarios that are subject to change.

For information and questions regarding ATS, please contact the e-Help Desk at 866-255-0654.

Modernized e-File (MeF) Assurance Testing System (ATS)

Tax year 2026 Modernized e-File schema and business rules for individual tax returns and extensions