Correspondence

Edition 5: Making Tax Digital for Income Tax — software developer newsletter

Published 29 July 2026

Welcome to the July edition of the Making Tax Digital (MTD) for Income Tax software developer newsletter.

This edition includes updates on:

• API lifecycle changes and actions for developers
• operational updates, service improvements and live service issues (LSIs)
• GOV.UK guidance updates
• customer communications and awareness activity
• developer engagement opportunities and upcoming events

As the service continues to evolve, these updates are intended to help you plan ahead, support your users, and understand where HMRC is making improvements.

API lifecycle updates

To help you plan future development activity, please continue to review the latest API versions, deprecation timelines and retirement dates on the Making Tax Digital for Income Tax roadmap.

What you need to know

Lifecycle updates you need to know include:

• API versions are deprecated shortly after a newer version is released — during the deprecation period, existing subscribers can continue to use the deprecated version, but new subscriptions are not permitted
• the standard deprecation period is 6 months before the older version is retired and removed from the platform
• HMRC will continue to communicate upcoming API retirements to software developers so that any required migration activity can be planned in advance

Upcoming retirements requiring attention

The following API versions are currently scheduled for retirement on 16 October 2026.

API	Current Version	Retirement Date
Individuals Capital Gains Income API	v2	16 October 2026
Individuals Reliefs API	v2	16 October 2026

Please review your software integrations and migrate to later API versions where required before these retirement dates.

Live service operation

Key developer live service reminders

To help you support your customers and minimise avoidable referrals, we’ve pulled together the following key reminders from recent live service investigations.

Q1 submissions — reporting elections

Customers are automatically set to standard reporting when they sign up to MTD. A reporting election is only required where a customer wishes to move to calendar reporting. If a customer changes reporting type, please allow time for the change to be reflected before making submissions and ensure their obligations have updated before submitting a Q1 update. If the obligations do not correctly update in a timely manner, when raising an LSI, include the customer’s reporting type and MTD sign-up year to help HMRC investigate more quickly.

Q1 obligation fulfulment

Before raising a Live Service Incident, check that the submission covers the full quarterly obligation period. HMRC analysis has identified cases where obligations remained open because the submitted period did not cover the entire quarter.

Missing obligations

HMRC is addressing an issue affecting a very small number of customers whose quarterly obligations were not created during sign-up. Affected customers will be unable to make a Q1 submission until corrective action is completed. Corrective action is expected to be completed by the end of July.

Onboarding

The Self Assessment Individual Details API now returns a new 403 error response: Client_Not_MTD_Enrolled. This will be returned where the National Insurance number supplied is not signed up for MTD and should be handled within customer onboarding journeys where appropriate.

Agent services

Supporting Agents have restricted API access and may receive a 403 Not Authorised response when attempting to access APIs available only to Main Agents. Please check whether the agent is acting as a Main Agent or Supporting Agent before raising an issue with HMRC.

Repayments

A fix is being rolled out for a small number of repayment cases linked to customers who submitted their return through the Self Assessment route rather than MTD-compatible software. Customers awaiting repayment should avoid submitting additional 2025 to 2026 returns through software while their case is being resolved.

Raising live service issues

Please continue to raise live service issues through your account manager by the MTD Software Vendors mailbox at makingtaxdigital-softwarevendors@hmrc.gov.uk.

Please make sure the LSI template is completed with the relevant details of the issue.

Planned downtime

For the latest planned downtime, visit the API Platform Status page.

HMRC carefully considers the impact on customers before scheduling downtime. Planned maintenance helps ensure services remain secure and reliable.

GOV.UK guidance updates

We’ve highlighted recent updates to MTD for Income Tax guidance, including qualifying income, sign-up journeys, customer support and changes in circumstances.

What’s changed

Qualifying income

Updates made on qualifying income include:

• clarification on how Self Assessment amendments can affect qualifying income
• new guidance for customers whose relevant income sources have ceased

Read more about working out your qualifying income for Making Tax Digital for Income Tax.

Help and support in MTD

For information about help and support in MTD we’ve added:

• guidance on refunds
• information for customers who sign up for the wrong tax year
• links to the HMRC Digital Assistant

Read more information at Use Making Tax Digital for Income Tax — Help and support.

Sign-up guidance

Updates made on the sign-up guidance include:

• clarification that volunteers can sign up for either the current tax year or the next tax year
• general amendments to improve clarity following user research

Read more about signing up for Making Tax Digital for Income Tax.

Changes in circumstances

Updates made on changes in circumstances include:

• new guidance covering customers adding or ceasing income sources
• updated information on amendments, qualifying income, opting out and participating as an MTD volunteer

Read more information at Use Making Tax Digital for Income Tax — If your circumstances change.

What developers should know

These updates may lead to customer queries relating to qualifying income, sign-up options, changes in circumstances, refunds and MTD eligibility. We recommend reviewing the updated guidance and ensuring support teams are aware of the latest information.

MTD communications update

Communications resources

We recently issued our news release, reminding people that the deadline for the first MTD quarterly update is approaching.

Plus, the latest campaign assets are available on our Stakeholder toolkit, should you wish to use them in your planned communications.

Customer communications and awareness activity

In addition to the communications resources available for stakeholders, HMRC continues to deliver customer-facing communications and awareness activity to support the wider rollout of Making Tax Digital for Income Tax.

Quarterly update reminders

Customers who signed up to Making Tax Digital for Income Tax from April 2026 and miss the first quarterly update deadline on 7 August 2026 will receive a reminder letter from HMRC. Letters are scheduled to be issued from October 2026 and will explain the action customers need to take to bring their obligations up to date. Customers who have opted to receive digital communications may also receive up to two reminder messages through their online services.

In-service messaging

Customers submitting a 2025 to 2026 Self Assessment tax return with qualifying income over £30,000 will see a message within the online Self Assessment service explaining that the way they report their income is changing and directing them to further guidance on preparing for Making Tax Digital for Income Tax.

Making Tax Digital awareness letters

From Autumn 2026, HMRC will issue awareness letters to customers with qualifying income over £30,000 who submit a 2025 to 2026 tax return. Letters will be issued in phases through to early 2027 and will explain how to prepare for and sign up to MTD for Income Tax.

Enhanced customer and agent support

HMRC has enhanced both customer and agent helplines to support Making Tax Digital for Income Tax. Improvements include updated recorded messages, better signposting to GOV.UK guidance and an SMS service that sends links to relevant support information directly to callers’ mobile phones. Current messaging includes information about the first quarterly update deadline.

What this means for developers

As awareness activity increases, customers may contact you after receiving HMRC letters, online messages or helpline communications. We recommend ensuring your support teams are familiar with the upcoming quarterly update requirements and sign-up guidance so they can help customers prepare for Making Tax Digital for Income Tax.

Get involved, feedback and support

Developer engagement

You can get in touch with us:

• by the HMRC Developer Forum — access the HMRC Developer Hub
• at the next Technical Forum on 8 September 2026
• by completing the software developer feedback survey to help us improve future newsletters

Developer queries

To help us manage and respond effectively, please send all developer queries to the MTD Software Vendors Mailbox at makingtaxdigital-softwarevendors@hmrc.gov.uk.

Next edition

The next edition is planned for 28 August 2026.

Thank you for your continued engagement and support. If you have feedback on this newsletter or the MTD for Income Tax service, please complete our Software Developer Feedback Survey.