Upcoming Change: IRIS 1099s

The Montana Department of Revenue will soon implement updated requirements for electronic information returns submitted through the IRIS API Solution. Please review the upcoming changes outlined below to ensure a smooth transition once the update takes effect.

Accepted File Formats (Future Requirement)

• Only IRIS XML files will be accepted.
• CSV files will not be supported.
• Publication 1220 files will not be accepted, including for prior-year submissions.

Submission Sources

• API submissions will be supported under the new requirements.
• TAP submissions will continue to be allowed but will be limited to no more than 100 returns per file.

Scope of Applicability

These changes will apply to all tax years still within the statutory filing period.

Approved Vendor Resources

Updated lists of approved vendors will continue to be available on the Montana Department of Revenue website for:

• 1099s
• W-2s
• MW-3s

Additional details, including implementation timelines and transition guidance, will be shared as they become available.

For questions, contact Information Governance at DORe-Services@mt.gov or (406) 444-4457.