HMRC has confirmed planned downtime for its Making Tax Digital (MTD) for Income Tax service in September 2026. The service goes dark from 5:00 PM on Friday, 11 September and doesn’t come back until 1:00 PM on Tuesday, 15 September.
The timing isn’t great. Around the same period, HMRC is starting to automatically sign up sole traders and landlords who should already be using MTD but haven’t joined yet.
So, if you’re an accountant, landlord, or self-employed, now’s a good time to check where you stand before the system shuts down.
What’s Actually Happening in September?
HMRC says the outage is down to scheduled maintenance. While it’s offline, nobody can access the MTD for Income Tax service, and agents and individuals won’t be able to complete new sign-ups either.
Businesses and accountants with outstanding registrations should therefore avoid leaving them until the last minute. If possible, they should complete pending sign-ups before 5:00 PM on 11 September. Otherwise, they will need to wait until the service returns on 15 September.
Why the Timing Matters
This outage couldn’t have landed at a busier point in the MTD rollout.
By 12 August, over 570,000 taxpayers had already signed up, and more than 436,000 had filed their first quarterly update. HMRC has previously said around 864,000 sole traders and landlords fall under the mandatory rules.
From September onward, HMRC starts automatically signing up anyone who should be using MTD but hasn’t registered. It’s rolling this out in stages over the coming months.
These sign-ups will be based on each taxpayer’s 2024/25 Self Assessment return. HMRC’s advice is to register yourself first if you can; that way, you know your details and income sources are set up correctly from day one, rather than leaving it to HMRC’s system.
| Key MTD Date | What It Means |
| 7 August 2026 | First quarterly update deadline |
| September 2026 | HMRC begins automatic MTD sign-ups |
| 11 September, 5 PM | Planned MTD service downtime begins |
| 15 September, 1 PM | MTD service expected to return |
| 7 November 2026 | Second quarterly update deadline |
Who Actually Needs to Worry About This?
MTD for Income Tax has applied since 6 April 2026 to sole traders and landlords earning more than £50,000 in qualifying annual income.
Here’s the part people often miss: that £50,000 test is based on gross income, before expenses, not net profit. HMRC also adds together income from self-employment and property when working out whether you’re over the threshold.
So, if you’ve assumed you’re safely outside MTD because your profit is under £50,000, it’s worth double-checking. Gross income tells a different story.
Behind on a Quarterly Update? Here’s Where You Stand
The first MTD quarterly update was due on 7 August 2026. If you should be filing under MTD and haven’t sent that update yet, it’s worth sorting out sooner rather than later.
The good news: HMRC isn’t handing out penalty points for late quarterly updates during the 2026/27 tax year. The bad news: the reporting duty is still there. You’ll need those updates filed before your tax return can be completed.
Next one up is 7 November 2026.
What to Do Before 11 September
If you’re an accountant, go through your client list now and flag anyone still needing MTD registration. Sole traders and landlords should check whether the £50,000 gross-income test catches them, and make sure HMRC has the right income sources on record, using HMRC-compatible cloud accounting software to keep everything up to date.
Already signed up? Worth checking whether that first quarterly update went in.
The outage itself is only a few days. But MTD deadlines don’t move around it, so getting ahead of the maintenance window now saves you a headache later, especially with the rollout already this busy.
At Lanop Business and Tax Advisors, we can help you check your MTD status, review your qualifying income, handle the registration steps, and get ready for the reporting deadlines coming up. Contact Lanop today; sorting your position out now makes the next stage of MTD a lot less stressful.
