Twenty-One Days to MTD Sign-Up Outage: Register Before 11 September
As of 21 August 2026, HMRC’s Making Tax Digital for Income Tax sign-up service goes offline in twenty-one days — from 5pm Friday 11 September to 1pm Tuesday 15 September — sole traders and landlords still unsigned should register this week.
HMRC’s Sign up for Making Tax Digital for Income Tax guidance, last updated 13 August 2026, confirms planned maintenance from 5pm on Friday 11 September 2026 to 1pm on Tuesday 15 September 2026. During that window you cannot sign up for Making Tax Digital for Income Tax. As of Friday 21 August, that outage is twenty-one calendar days away.
If you need Making Tax Digital for Income Tax for the 2026 to 2027 tax year — typically where qualifying self-employment and property income was over £50,000 on the 2024 to 2025 return — HMRC’s guidance is to sign up now, not after the maintenance window.
Who should treat the next three weeks as mandatory
Sole traders and landlords still outside Making Tax Digital who fall in the April 2026 cohort should complete sign-up, software links, and agent authorisations before 5pm on 11 September.
Agents should clear Agent Services Account MFA recovery and client authorisations first — a locked ASA during the outage leaves clients stuck even if their software is ready.
Voluntary joiners for later thresholds can still sign up, but mandatory filers should not share the final-week queue with leisurely volunteers.
Twenty-one-day prep checklist
Use HMRC’s “find out if and when you need to use Making Tax Digital for Income Tax” tool to confirm your year and exemptions.
Sign up each income source that still appears on Self Assessment records — including ceased sources that HMRC has not yet removed.
Link compatible software and send a test quarterly update path before the outage so September is not your first live connection attempt.
Diary the outage on shared practice calendars: 11 September 5pm to 15 September 1pm is unavailable for new sign-ups.
How FinnAccountings helps before the sign-up outage
Digital records that match bank feeds make quarterly updates faster once you are signed up. FinnAccountings helps Ireland and UK sole traders and limited companies prepare bookkeeping and tax packs with Chartered Accountant insight before you or your ICAEW/ACCA or Chartered Accountant (Ireland) adviser files. Start a free trial for review-ready drafts — we prepare records; we do not sign you up to Making Tax Digital or submit quarterly updates to HMRC on your behalf.
Related reading
Today’s twenty-day outage briefing is the live countdown beside this pack.
Yesterday’s three-week outage briefing still maps the full maintenance narrative.
The original maintenance briefing remains useful for agent and software sequencing.
Keep agent MFA lockout prevention beside your ASA workflow.
Sources & references
This article draws on official guidance from the sources below.
- Sign up for Making Tax Digital for Income Tax
HM Revenue & Customs · Accessed 2026-08-21 - Find out if and when you need to use Making Tax Digital for Income Tax
HM Revenue & Customs · Accessed 2026-08-21 - Sign up your client for Making Tax Digital for Income Tax
HM Revenue & Customs · Accessed 2026-08-21
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