Information for each tax year/processing year is listed below. Publication 5164, Test Package for Electronic Filers of Affordable Care Act (ACA) Information Returns (AIR) PDF has additional details on the different scenarios and who is required to test for each tax year. General instructions PDF for tax years 2022 and beyond. Tax year 2024/processing year 2025 Tax Year 2024/Processing year 2025 AATS testing: 11/01/2024. These scenarios use the most current copy of the forms. AATS scenarios Tax period AATS known issues and solutions 1094B/1095B ZIP 1094C/1095C ZIP 2024 Update: TBD Known issues for scenarios Tax year 2023/processing year 2024 Tax year 2023/Processing year 2024 AATS testing began on November 1, 2023. AATS scenarios Tax period AATS known issues and solutions 1094B/1095B ZIP 1094C/1095C ZIP 2023 Update: TBD Known issues for scenarios Tax year 2022/processing year 2023 Tax year 2022/Processing year 2023 AATS testing began on November 1, 2022. AATS scenarios Tax period AATS known issues and solutions 1094B/1095B ZIP 1094C/1095C ZIP 2022 Update: TBD Known issues for scenarios Tax year 2021/processing year 2022 Tax year 2021/Processing year 2022 AATS testing began on November 2, 2021. AATS instructions AATS scenarios Tax period AATS known issues and solutions AATS instructions PDF 1094B/1095B ZIP 1094C/1095C ZIP 2021 Update: TBD Known issues for scenarios Tax year 2020/processing year 2021 Tax year 2020/Processing year 2021 AATS testing began on November 2, 2020. AATS scenarios Tax period AATS known issues and solutions 1094B/1095B ZIP 1094C/1095C ZIP 2020 Update: TBD Known issues for scenarios Tax year 2019/processing year 2020 Tax year 2019/Processing year 2020 AATS testing began on November 1, 2019. Predefined AATS Scenarios Instructions Predefined AATS narratives Predefined AATS answer keys Tax periods AATS scenario known issues and solutions Predefined scenario instructions PDF 1094B/1095B ZIP 1094C/1095C ZIP 1094B/1095B ZIP 1094C/1095C ZIP 2019 Update: 9/28/2020 Known issues for scenarios PDF Criteria-based AATS scenarios Instructions Criteria-based AATS narratives AATS answer keys Tax periods AATS scenario known issues and solutions Criteria-based AATS scenarios instructions PDF 1094B/1095B PDF 1094C/1095C PDF N/A: Criteria-based scenarios do not have answer keys since the transmitter has more flexibility in the data that is submitted. Please refer to Publication 5164 for more details. 2019 Update: 9/28/2020 Known issues for scenarios PDF Tax year 2018/processing year 2019 Tax year 2018/Processing year 2019 ACA AATS testing began on November 2, 2018. Predefined AATS scenarios Instructions Predefined AATS narratives Predefined AATS answer keys Tax periods AATS scenario known issues and solutions Predefined scenario instructions PDF 1094B/1095B ZIP 1094C/1095C ZIP 1094B/1095B ZIP 1094C/1095C ZIP 2018 Update: 11/01/2018 Known issues for scenarios PDF Criteria-based AATS scenarios Instructions Criteria-based AATS narratives AATS answer keys Tax periods AATS scenario known issues and solutions Criteria-based AATS scenarios instructions PDF 1094B/1095B PDF 1094C/1095C PDF N/A: Criteria-based scenarios do not have answer keys since the transmitter has more flexibility in the data that is submitted. Please refer to Publication 5164 for more details. 2018 Update: 11/01/2018 Known issues for scenarios PDF Tax year 2017/processing year 2018 Tax year 2017/Processing year 2018 ACA AATS testing began on October 31, 2017. Predefined AATS Scenarios Instructions Predefined AATS narratives Predefined AATS answer keys Tax periods AATS scenario known issues and solutions Predefined scenario instructions PDF 1094B/1095B ZIP 1094C/1095C ZIP 1094B/1095B ZIP 1094C/1095C ZIP 2017 Update: 11/01/2018 Known issues for scenarios PDF Criteria-based AATS scenarios Instructions Criteria-based AATS narratives AATS answer keys Tax Periods AATS scenario known issues and solutions Criteria-based AATS Scenarios Instructions PDF 1094B/1095B PDF 1094C/1095C PDF N/A: Criteria-based Scenarios do not have answer keys since the transmitter has more flexibility in the data that is submitted. Please refer to Publication 5164 for more details. 2017 Update: 11/01/2018 Known issues for scenarios PDF Tax year 2016/processing year 2017 Tax year 2016/Processing year 2017 ACA AATS testing was open for testing in early November 2016. Predefined AATS Scenarios Instructions Predefined AATS narratives Predefined AATS answer keys Tax periods AATS Scenario known issues and solutions Predefined scenario instructions PDF 1094B/1095B ZIP 1094C/1095C ZIP 1094B/1095B ZIP 1094C/1095C ZIP 2016 Update: 01/19/2017 Known issues for scenarios PDF Criteria-based AATS scenarios Instructions Criteria-based AATS Narratives AATS answer keys Tax periods AATS scenario known issues and solutions Criteria-based AATS scenarios instructions PDF 1094B/1095B PDF 1094C/1095C PDF N/A: Criteria-based scenarios do not have answer keys since the transmitter has more flexibility in the data that is submitted. Please refer to Publication 5164 for more details. 2016 Update: 01/19/2017 Known issues for scenarios PDF Tax year 2015/processing year 2016 Tax year 2015 ACA AATS was open for testing in early November 2015 for information returns that were processed in 2016. IRS opened AATS in November using a character-by-character comparison tool, however testing has migrated to a more robust environment in January that include business rules validations. Special instructions are included in the ReadMe files providing an explanation of the AATS functionality now available. Please review the appropriate ReadMe file before programming the AATS scenarios. Links for the ReadMe files can be found in the comments section below. AATS scenarios AATS scenario forms AATS answer keys Tax periods AATS scenario known issues and solutions Comments 1094B/1095B ZIP 1094C/1095C ZIP 1094B/1095B ZIP 1094C/1095C ZIP 2015 Known issues PDF ReadMe PDF Return to Affordable Care Act Information Returns (AIR)