Wow, as if we didn't have enough challenges already!
"Subject: New Form 1040 Business Rules and Schemas are Scheduled for Delivery on or around February 10, 2022
Attention: Software Developers, Return Transmitters and Authorized IRS e-file Providers/EROs
Software Developers and State organizations may download Modernized e-File (MeF) schemas and business rules from their e-Services mailbox. To access these files, you must have:
An active e-Services account
An e-file application with the Software Developer or State provider option with the associated tax type of 1040, 2350, 4868, 56 or 9465
Tax Year 2021 / Processing Year 2022 Business Rules and Schemas
Form 1040 Series 2021v5.2
Form 2350 2021v1.1
Form 4868 2021v1.1
Form 56 CUv22.1
Form 9465 CUv24.1
Please visit the Modernized e-file (MeF) Schemas and Business Rules page on IRS.gov for more information about MeF Schemas and Business Rule."