The Tax year 2021 1065 Modernized e-File (MeF) Assurance Testing System (ATS) information is contained below. If you support these Forms, you will need to contact the e-Help Desk for testing. Please monitor this page for any ATS scenario updates. TY 2021 1065 MeF ATS scenarios 1065 MeF ATS Scenario 1 (Form 1065) PDF – (9/30/2021) 1065 MeF ATS Scenario 2 (Form 1065) PDF – (9/30/2021) 1065 MeF ATS Scenario 3 (Form 1065) PDF – (10/20/2021) 1065 MeF ATS Scenario 4 (Form 1065) PDF – (9/30/2021) 1065 MeF ATS Scenario A (Form 1065 K-1 Aggregator) PDF – (9/30/2021) 1065 MeF ATS Scenario B (Form 1065 K-1 Aggregator) PDF – (9/30/2021) For information and questions regarding ATS, please contact the e-help Desk at 866-255-0654. Modernized e-File (MeF) Assurance Testing System (ATS) updates Tax year 2021 1065 MeF schemas and business rules