Guidance

Self Assessment technical specifications (2026) for partnership returns

Use this technical documentation for partnership returns if you’re a software developer working with the Self Assessment online service.

• From: HM Revenue & Customs
• Published: 30 December 2025
• Last updated: 30 March 2026 — See all updates

Documents

Self Assessment Partnership RIM Artefacts version 1.0

ZIP, 1.2 MB

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Partnership Special Exclusion version 1.0

ODT, 32.4 KB

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Details

Partnership returns technical specifications for software developers working with the Self Assessment online service.

Published 30 December 2025

Last updated 30 March 2026 + show all updates

1. 30 March 2026

   A new attachment 'Partnership Special Exclusion version 1.0’ has been added.

2. 30 December 2025

   First published.