HMRC publishes CT600 V3 (2027) RIM artefacts for Corporation Tax software developers
A short item for the people who actually build Corporation Tax filing software. HMRC has added the next-year CT600 artefact set and reshuffled the live and test versions. It binds no taxpayer directly but sets the technical rails for every CT600 return filed through commercial and in-house software. Here is what moved and what to watch on the implementation status.
- CT600 V3 (2026) Artefacts V1.995 was renamed to CT600 V3 (2027) Artefacts V1.995 on 12 October 2026.
- V1.995 (version date 25 September 2026) is awaiting implementation into LTS, TPVS and live.
- CT600 V3 (2026) Artefacts V1.994 and CT600 V2 (2009) Artefacts V3.99 are currently in LTS, TPVS and live.
Executive summary
HM Revenue & Customs updated its guidance page carrying the Corporation Tax technical specifications — the RIM artefacts used by Corporation Tax software developers to build and validate CT600 returns — on 12 October 2026. The page was first published…
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Source documents
https://www.gov.uk/government/publications/corporation-tax-technical-specifications-ct600-rim-artefactsRead by Regulus 15 Oct 2026 at 14:06 UTC
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