Crystallisation Deadline Escalation — How It Works
Crystallisation Deadline Escalation
The crystallisation deadline escalation workflow automatically monitors whether your organisation has completed its End of Period Statement (EOPS) crystallisation before the HMRC Making Tax Digital deadline of 31 January.
What Is Crystallisation?
Under HMRC Making Tax Digital for Income Tax Self Assessment (MTD ITSA), after submitting all four quarterly updates for a tax year, landlords must crystallise their final tax position. This is the digital equivalent of filing your Self Assessment return. The deadline is 31 January following the end of the tax year (e.g. 31 January 2026 for the 2024–25 tax year).
Failure to crystallise by this date may result in HMRC penalties.
How the Escalation Workflow Works
From 1 December each year through to 31 January, the platform runs a daily automated check at 08:00 UTC across all organisations.
Eligibility Check
An organisation is included in the escalation sweep if:
- It has at least one
quarterly_summaryin a submitted state for the tax year that ended on 5 April. - Its audit log does not contain an
hmrc.finalise.completedentry — meaning crystallisation has not yet been recorded.
Escalation Schedule
Once an organisation is flagged, notifications are sent to all organisation members at the following points:
| Days Before 31 January | Message Severity |
|---|---|
| 60 days | ℹ️ Reminder |
| 30 days | ℹ️ Reminder |
| 14 days | ⚠️ Urgent Reminder |
| 7 days | ⚠️ Urgent Reminder |
| 1 day | ⚠️ Urgent Reminder |
| Deadline day (31 Jan) | 🔴 Error — Immediate Action Required |
Once the hmrc.finalise.completed audit log entry is recorded (i.e. crystallisation is submitted via the HMRC MTD API), the organisation is automatically excluded from further escalation sweeps for that tax year.
Who Receives Notifications?
All active organisation members (org_members) associated with the flagged organisation will receive escalation notifications through the platform's notification system.
How to Complete Crystallisation
To stop receiving escalation reminders, you must finalise your tax return through the platform:
- Confirm all four quarterly submissions for the tax year are marked as submitted.
- Review your End of Period Statement (EOPS) summary.
- Submit your crystallisation declaration via the HMRC Making Tax Digital API connection.
- The platform will log an
hmrc.finalise.completedaudit entry and no further reminders will be sent.
Note: Crystallisation is irreversible once submitted to HMRC. Ensure all income and expense figures are correct before proceeding.
Key Dates Reference
| Date | Event |
|---|---|
| 6 April | Start of new tax year |
| 5 April | End of tax year |
| 1 December | Crystallisation escalation sweep begins |
| 31 January | HMRC crystallisation deadline |