The tables below provide links to the tax year 2023 release memorandum, extensible markup language schema, and business rules for the Modernized e-File (MeF) 1040 series and extensions. Throughout the year, multiple versions of schema and business rules may be in use at the same time. For each version, the tables below reflect the effective dates in the Assurance Testing System (ATS) and Production System. Tax year 2023 documents Tax year 2023 accepted forms and schedules for individual tax returns and extensions XLSX Tax year 2023 form 1040 series and extensions forms and attachments listing XLSX Tax year 2023 recommended portable document files (PDFs) attached to 1040 MeF submissions XLSX updated 06/06/2024 Tax year 2023 Form 1040 series Version Date available in SOR * ATS date Production date Comments 2023v1.0 06/08/2023 Not valid in ATS Not valid in production 2023v2.0 07/20/2023 Not valid in ATS Not valid in production 2023v3.0 08/31/2023 10/23/2023 – 11/19/2023 Not valid in production 2023v4.0 10/12/2023 11/19/2023 – 12/17/2023 Not valid in production 2023v5.0 12/28/2023 12/17/2023 1/29/2024 12/28/2023 – Complete schema and business rule packages. 2023v5.1 02/08/2024 03/03/2024 03/17/2024 01/29/2024 – Complete schema and business rule packages. 2023v5.2 04/18/2024 06/02/2024 06/16/2024 04/11/2024 – Complete schema and business rule packages. 2023v5.3 10/10/2024 11/17/2024 To be determined 10/09/2024 – Complete schema and business rule packages. Tax year 2023 Form 4868 Version Date available in SOR * ATS date Production date Comments 2023v1.0 06/08/2023 10/23/2023 – 11/19/2023 Not valid in production 2023v1.1 10/12/2023 11/19/2023 1/29/2024 Tax year 2023 Form 2350 Version Date available in SOR * ATS date Production date Comments 2023v1.0 06/08/2023 10/23/2023 – 11/19/2023 Not valid in production 2023v1.1 10/12/2023 11/19/2023 1/29/2024 Form 9465 Version Date available in SOR * ATS date Production date Comments CUv25.1 10/12/2023 11/19/2023 – 12/17/2023 Not valid in production CUv26.0 11/16/2023 12/17/2023 1/29/2024 Form 56 Version Date available in SOR * ATS date Production date Comments CUv23.1 10/12/2023 11/19/2023 1/29/2024 * Secure Object Repository (SOR)