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) 2018. Included are the 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 and Publication 4164 PDF. 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 Memos - 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 2018 Documents Tax Year 2018 8849 MeF Accepted Forms and Schedules PDF Tax Year 2018 8849 MeF Return Due Dates PDF Tax Year 2018 Stylesheets: MeF Stylesheets Tax Year 2018 Known Issues and Solutions XLSX – Revised 08/07/2020 TY2018 Valid XML Schemas and Business Rules for Form 8849 Modernized e-File Version Available Date ATS Date Production Date Comments 2018v1.0 09/27/2017 Start: 10/30/2017 End: TBD Start: 01/08/2018 End: TBD Business Rule Change Page (02/14/2018) Current Valid XML Schemas and Business Rules for Form 8849 Modernized e-File (MeF) Schemas and Business Rules