HMRC review of the supplied concerns — 8 October 2026

Conclusion
The pasted review does not describe this copy accurately in several places.
ChannelRouting and software identity were already implemented, with 170 passing
offline checks. The 2027/28 schema pack and wider automated coverage were missing.
Those have now been added. This is not an HMRC recognition certificate or a claim
that the complete payroll engine has been independently certified.

Comparison and actions
1. ChannelRouting / Vendor ID / Product / Version: already present.
   RtiDocumentBuilder emits the namespaced elements in the correct order.
   RtiSoftwareIdentity is init-only. Gateway settings capture the assigned Vendor
   ID; product is SMRC Payroll and version comes from assembly release metadata.
   Missing identity blocks dispatch. No fictitious Vendor ID has been configured.
   Release process must set InformationalVersion and the assigned Vendor ID.

2. No test project: incorrect. SMRC.Tests already existed as an executable test
   harness. It is now included in SMRC-App.sln and has broader offline coverage.
   Run it with dotnet run, not dotnet test (it is not an xUnit/MSTest project).

3. 2027/28 RIM v2.0: real omission, fixed.
   Official FPS/EPS XSD, Schematron, XSLT and GovTalk schema installed unchanged.
   Registry resolves the correct v1-0/v2-0 artefact names and /27-28/2 namespaces.
   The XML signature dependency is the existing bundled standard schema; it was
   not supplied in the new HMRC ZIP. Production filing for 2027/28 is blocked.
   PayrollEngine already rejects a tax year different from its loaded rule pack.
   Installing XML definitions does not install next year's calculation rules.

4. Calculation and XML regression testing: expanded to 441 passing checks.
   Coverage includes fixed PAYE codes (including Scottish and Welsh), cumulative
   correction, M1, zero emergency pay, NT refund, all 17 listed NI categories,
   annual director NI, loan plans 1/2/4/5 alongside postgraduate deductions,
   SSP full-rate and low-earner weeks, and unsupported payroll case rejection.
   Across 2025/26, 2026/27 and 2027/28: schema/rules loading, GovTalk routing,
   FPS normal/starter/leaver/after-leaving/payroll-ID-change/late/corrected/final
   submissions and AN/AL reporting, EPS no-payment/recoveries/CIS/levy/final,
   Employment Allowance claims for 2026/27 onwards, withdrawals and zero recovery
   corrections. Tests include deterministic XML/IRmarks, a hand-authored golden
   no-payment EPS business body and negative schema validation.
   Amount expectations use the published 2026/27 rates, not engine-generated
   expected values. XML scenario data are synthetic and never sent by this run.

5. Specialist FPS fields: omission confirmed, but not universal requirements.
   Passport and partner structures are optional in XSD; whether needed depends
   on the employee's circumstances. Foreign-country addresses require their own
   workflow. Adding blank elements would not implement that workflow.
   Pension recipients, expatriates, modified schemes and troncs remain excluded.
   The visible PayrollCapabilities catalogue now explicitly identifies missing
   identity/address workflows and the validation-only status of 2027/28.
   Recognition applications must describe this limited scope.

6. Transaction Engine: client already supports submission/status conversations.
   Added an explicit Sandbox-only ETS runner with local validation and saved
   response evidence. It does not send anything during ordinary regression runs.
   This environment has no Vendor ID, sender ID or password configured; no real
   ETS request was attempted. SDST-assigned scenarios/credentials are still needed.

Remaining recognition/release evidence
- SDST recognition scenarios and actual ETS acceptance/receipt evidence.
- Official PAYE test-vector coverage of allowance tables, cumulative sequences,
  emergency and tax-year transitions; full director AN/AL reconciliation flows;
  changes in loan obligations and persisted YTD corrections.
- Complete eligibility, schedule, persistence and correction coverage for every
  statutory-pay workflow. Current SSP examples and family-pay XML checks do not
  establish that breadth of coverage.
- Full golden XML fixtures for every supported scenario; current golden coverage
  is the no-payment EPS body, alongside field assertions and deterministic checks.
- The installed 2025/26 v1 rules require DeMinimisStateAid for an Employment
  Allowance claim. This draft model cannot supply it. Such historical claims fail
  official validation; do not claim this historical capability. Confirm the
  appropriate historical pack/workflow with SDST before enabling it.
- Set release InformationalVersion and assigned Vendor ID in deployment.

Commands (run from SMRC-App-Source-Fixed)
  dotnet run --project SMRC.Tests/SMRC.Tests.csproj
  dotnet build SMRC-App.sln --no-restore

ETS, once Sandbox credentials and SDST synthetic test data are available:
  Set SMRC_HMRC_RTI_ENVIRONMENT=Sandbox and configure SMRC_HMRC_RTI_VENDOR_ID,
  SMRC_HMRC_RTI_SENDER_ID and SMRC_HMRC_RTI_PASSWORD in the process environment.
  dotnet run --project SMRC.Tests -- --ets <test-IRenvelope.xml> <new-evidence-directory>
  Use only HMRC test credentials and test employer references. The runner saves
  the payload and response evidence, not the credential-bearing GovTalk request.
  If delivery is uncertain, inspect/recover the correlation before retrying.

Sources checked
HMRC basic guide (Vendor ID, ETS and recognition process):
https://www.gov.uk/guidance/basic-guide-for-xml-software-developers
HMRC 2027/28 RIM (test service October 2026; live service March 2027):
https://www.gov.uk/government/publications/real-time-information-internet-submissions-2027-to-2028-technical-specifications
Official downloaded archive:
https://assets.publishing.service.gov.uk/media/6a9fe38b5f6e942efe37eeb1/RTI-RIM-2028-v2-0.zip
Archive SHA256: FF352218936C24E716F2DB4912A6FF1D849F34F82A17413C00EA3C5EB1097FA1
HMRC rates and thresholds used for independent regression expectations:
https://www.gov.uk/guidance/rates-and-thresholds-for-employers-2026-to-2027
HMRC GovTalk header guidance:
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/637334/hints-tips.pdf

The vending-site material in the pasted text is unrelated to payroll software
and was excluded from this review.
