The links below provide information and technical guidance for Software Developers and Transmitters who are interested in developing software for the Modernized e-File (MeF) Forms 1120, 1120-F, and 1120-S for Tax Year 2023. Developers and other Authorized IRS e-file Providers can find information on e-filing returns through MeF in Publication 4163PDF and Publication 4164PDF. Directions for Corporations required to e-file can be found through the e-file for Large and Mid-Size Corporations website. Test Scenarios for the 1120 Form Family can be found on the Modernized e-File (MeF) Assurance Testing System (ATS) page. Extensible Markup Language (XML) Schemas, Business Rules, and Release Memorandum - Throughout the year, multiple versions of these documents may be in use at the same time. Special attention should be paid to the Release Memo issue date and the projected start and end dates for Assurance Testing System and Production. Form 1120 Schemas and Business Rules are now distributed through the Registered User Portal and your e-services mailbox. This mailbox is part of the Secure Object Repository (SOR). Users will access their mailbox in their existing e-services account to pick up the Schemas and Business Rules packages. Instructions for accessing the SOR mailbox Tax year 2023 documents Tax Year 2023 1120 MeF Accepted Forms and SchedulePDF Tax Year 2023 1120 MeF Forms Attachment ListingXLSX Tax Year 2023 1120 MeF Return Due DatesPDF Tax Year 2023 Stylesheets: MeF Stylesheets Tax Year 2023 Known Issues and SolutionsXLSX – Revised 04/12/2024 Form 1120, 1120-F, 1120-S links to TY2023 release memos Version Available Date ATS Date Production Dates Comments 2023v5.2 04/18/2024 Start: 06/02/2024 End: TBD Start: 06/16/2024 End: TBD Valid for ATS and Production 2023v5.1 02/08/2024 Start: 03/03/2024 End: TBD Start: 03/17/2024 End: TBD Updated business rules available Valid for ATS and Production 2023v5.0 11/13/2023 Start: 12/17/2023 End: TBD Start: 01/16/2024 End: TBD Updated business rules available 12/28/2023 2023v4.0 10/12/2023 Start: 11/19/2023 End: 12/16/2023 Not available for Production Not valid for Production 2023v3.0 08/31/2023 Start: 10/23/2023 End: 11/18/2023 Not available for Production Not valid for Production 2023v2.0 07/20/2023 Not available for ATS Not available for Production Not valid for ATS and Production 2023v1.0 06/08/2023 Not available for ATS Not available for Production Not valid for ATS and Production Valid XML schemas and business rules for 1120/1120-F/1120-S Modernized e-File (MeF) schemas and business rules
