The following links 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) 2026. Included are the Extensible Markup Language (XML) Schemas, Business Rules, Release Memorandum and specific instructions.
Developers and other authorized IRS e-file providers can find information on e-filing returns through MeF in the Publication 4163 PDF. Test Scenarios for Form 8849 can be found on the Modernized e-File (MeF) Assurance Testing System (ATS) page.
Extensible Markup Language (XML) Schemas, Business Rules and Release Memo - 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 (ATS) and Production.
Tax year 2026 documents
- Tax year 2026 8849 MeF accepted forms and schedules – Not available
- Tax year 2026 8849 MeF return due dates – Not available
- Tax year 2026 stylesheets: MeF stylesheet – Not available
- Tax year 2026 known issues and solutions – Not available
| Version | Available date | ATS date | Production date | Comments |
|---|---|---|---|---|
| 2026v1.0 | 6/25/2025 | Not valid for ATS | Not valid for production |