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 1041. You will find the Extensible Markup Language (XML) Schemas, Business Rules, and other useful information separated by tax year. Form 1041 Production and Assurance Testing System (ATS) - Current valid schema Tax year 2024 2023 2022 2021 Modernized e-File (MeF) Schemas and Business Rules