· Customs & Trade · 2 min read
CDS (UK) — What Changed in the Last 6 Months (Mar–Aug 2025)
A practical, trader-focused summary of HMRC’s Customs Declaration Service updates from March to August 2025—data-element tweaks, tariff notices, release notes, and service advisories.
At-a-glance (Mar → Aug 2025)
- CDS v3 guidance refreshed — HMRC updated the Import Declaration Completion Instructions on 17 Jul 2025 (gov.uk).
- Document codes (DE 2/3) changed in August — New/updated entries incl. X809 (7 Aug), C809 (12 Aug), and Y864 scope widened (28 Aug) (gov.uk appendix 5A).
- Measurement unit codes refreshed — Appendix tables updated 13 Aug 2025 (gov.uk appendix 6).
- CDS 4.8.x releases (late May–June) — Release 4.8.0 published 27 May with follow-on notes covering API/dis service, Cash Account dashboard, NI licence verification, CERTEX scheduling (ASM updates).
- Tariff updates you may feel downstream in CDS — MFN/Authorised Use measures (16 May), commodity code structure alignment (6 Aug), and a suspension tweak (20 Aug) (UK Integrated Tariff).
- Service availability notice — Planned maintenance messaging updated 22 Aug 2025 (HMRC service issues).
What to actually change in your configurations
1) Data Elements & Codes (August updates)
- DE 2/3 (Documents & Other References)
- Add support for X809 (from 7 Aug) and C809 (from 12 Aug).
- Update mappings for Y864 (from 28 Aug).
- Action: refresh code lists in your broker/ERP; rerun unit tests.
- Source: gov.uk appendix 5A
2) Measurement Unit Codes (13 Aug)
- Sync to HMRC’s 13 Aug 2025 list.
- Action: refresh enumerations; confirm conversions.
- Source: gov.uk appendix 6
3) CDS Guidance Refresh (17 Jul)
- Revised Import Declaration Completion Instructions (Vol. 3).
- Action: update inline help and validation rules.
- Source: gov.uk guide
4) Platform releases & ops notes (May–June)
- CDS Release 4.8.0 + follow-on notes: DIS API CO support, Cash Account dashboard, NI licence verification behaviour, CERTEX scheduling.
- Source: ASM CDS updates
5) Tariff & Code Structure changes that ripple into CDS
- 16 May — MFN/Authorised Use measures + structure alignment.
- 6 Aug — Commodity code structure alignment (Ch. 07/08).
- 20 Aug — Suspension measure correction (2918999067).
- Source: UK Integrated Tariff
6) Service Availability (22 Aug notice)
- HMRC flagged delayed responses during maintenance.
- Source: Service availability & issues
Quick compliance checklist
- Update DE 2/3 doc codes (X809, C809, Y864) — appendix 5A
- Refresh Measurement Unit Codes — appendix 6
- Re-sync Import Instructions Vol. 3 — guide
- Regression test DIS + NI licence flows — ASM updates
- Rebuild classifications & measures — UK Tariff
- Adjust monitoring for maintenance latency — service issues