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) Form 8849 for Tax Year (TY) 2021. Included are the Extensible Markup Language (XML) Schemas, Business Rules, Release Memoranda, and specific instructions. Developers and other Authorized IRS e-file Providers can find information on e-filing returns through MeF in the Publication 4163PDF and Publication 4164PDF. Test Scenarios for Form 8849 can be found on the Modernized e-File (MeF) Assurance Testing System (ATS) Page. XML Schemas, Business Rules, and Release Memoranda - Throughout the year, multiple versions of these documents may be in use at the same time. Special attention should be paid to the Release Memorandum issue date and the projected start and end dates for Assurance Testing System (ATS) and Production. Tax Year 2021 Documents Tax Year 2021 8849 MeF Accepted Forms and SchedulesPDF Tax Year 2021 8849 MeF Return Due DatesPDF Tax Year 2021 MeF Stylesheets Tax Year 2021 Known Issues and SolutionsXLSX – Revised 03/02/2023 TY2021 Valid XML Schemas and Business Rules for Form 8849 Modernized e-File Version Available Date ATS Date Production Date Comments 2021v2.0 10/16/2020 Start: 11/22/2020 End: TBD Start: 01/08/2021 End: TBD Business Rules Change Page dated 09/02/2021 Current Valid XML Schemas and Business Rules for Form 8849 Modernized e-File (MeF) Schemas and Business Rules
