The tables below provide links to the Tax Year 2021 Extensible Markup Language (XML) Schemas, Business Rules, and Release Memorandum for the Employment Tax Forms (Form 94x series). Throughout the year, multiple versions of Schemas and Business Rules may be in use at the same time. The table reflects the effective dates in the Assurance Testing System (ATS) and Production System, for each version. Tax year 2021 documents Tax Year 2021 94x MeF Accepted Forms and Schedules PDF Tax Year 2021 94x MeF ATS Information Tax Year 2021 94x MeF Forms and Attachment List XLSX Tax Year 2021 94x MeF Return Due Dates PDF Tax Year 2021 94x MeF Stylesheets Tax Year 2021 Known Issues and Solutions XLSX - Revised 03/26/2024 Tax year 2021 Form 94x (annual forms) Version Available Date ATS Dates Production Dates 2021v2.0 10/14/2021 Start: 11/21/2021 End: TBD Business Rules Change Page dated 12/28/2023 Tax year 2021 Form 941x (quarterly forms) Version Available Date ATS Dates Production Dates 2021v3.0 05/29/2021 Start: 06/20/2021 End: TBD Business Rules Change Page dated 12/28/2023 94x online signature PIN registration application Version Available Date ATS Dates Production Dates CUv3.0 05/17/2018 Start: 10/29/2018 End: TBD Start: 01/08/2019 End: TBD Form 9465 Version Available Date ATS Dates Production Dates CUv26.0 11/13/2023 Start: 12/17/2023 End: TBD Start: 01/29/2024 End: TBD CUv27.0 06/06/2024 Not valid in ATS Not valid in production Schemas and business rules for Employment Tax Modernized e-File (MeF) Forms Modernized e-File (MeF) program information
