Indiana has released an IRIS Tax Year 2026 Guide and IRIS Business Rules. Beginning January 1, 2027, the Indiana Department of Revenue will support the IRS’s new IRIS XML file format for supported 1099 forms, Form 1042-S, and Form W-2G. Indiana will also continue to support filing in the FIRE / Publication 1220 .txt format for tax year 2026 filings until September 2027 in order to help Indiana filers through the transition.
Indiana will generally follow the IRS IRIS Schema and business rules, in addition to several Indiana specific business rules. To submit IRIS files, all new and existing SFTP accounts must be updated to include tax type code 203, which will be available on December 17, 2026. IRIS files over 10MB must be submitted through SFTP, while files under 10MB should be submitted through INTIME.
The IRIS 2026 Tax Year Guide also includes information about acceptance and acknowledgements, corrections, abatement requests, and instructions for submitting a zero-dollar WH-3.
The Indiana IRIS 2026 Tax Year guide can be found here.
The IRIS Business Rules can be found here.
