HMRC has published the fifth edition of its Making Tax Digital for Income Tax software developer newsletter, dated 29 July 2026, with the July update focused on API lifecycle management, live service handling, revised GOV.UK guidance and customer communications ahead of the first quarterly filing deadline. The next edition is scheduled for 28 August 2026. (gov.uk)
The clearest operational deadline in the update is the retirement of two API versions on 16 October 2026. HMRC says Individuals Capital Gains Income API v2 and Individuals Reliefs API v2 are both due to be removed on that date, and repeats that deprecated versions are normally left in place for six months before retirement. In practice, that gives software suppliers a defined window to review integrations and move to later versions before service access is affected. (gov.uk)
HMRC’s live service guidance is framed around first-quarter submissions. Customers are placed on standard reporting when they sign up, with a reporting election needed only where calendar reporting is required. Where a reporting type is changed, the department says developers should wait for obligations to refresh before sending a Q1 submission, and should include the customer’s reporting type and MTD sign-up year when raising a live service issue about delayed updates. (gov.uk) The department has also narrowed the checks it expects suppliers to make before escalating a case. HMRC says some obligations have remained open because submitted data did not cover the full quarterly period, while a separate issue affecting a very small number of customers whose obligations were not created during sign-up is due to be corrected by the end of July 2026. (gov.uk)
Several of the July points amount to direct product changes rather than general background. The Self Assessment Individual Details API now returns a 403 response, Client_Not_MTD_Enrolled, where the National Insurance number used is not signed up to Making Tax Digital for Income Tax. HMRC also says Supporting Agents may receive a 403 Not Authorised response when trying to use APIs reserved for Main Agents, making agent status checks a more important part of onboarding and support design. (gov.uk) HMRC is also rolling out a fix for a small number of repayment cases involving customers who filed through the Self Assessment route rather than MTD-compatible software. While those cases are being resolved, the department says affected customers awaiting repayment should not submit additional 2025 to 2026 returns through software. (gov.uk)
The guidance section shows HMRC refining how the programme is explained to taxpayers and agents. Updates now cover how Self Assessment amendments can change qualifying income, what happens when relevant income sources cease, how refunds work in MTD, and what to do where a customer signs up for the wrong tax year. HMRC has also clarified that volunteers can join for either the current tax year or the next tax year, and has expanded its guidance on adding or ceasing income sources, amendments, opting out and volunteer participation. (gov.uk) For software firms, the effect is likely to be seen first in customer support. HMRC explicitly warns that the revised pages may prompt questions about eligibility, qualifying income, refunds, changes in circumstances and sign-up choices, which means product guidance and support scripts will need to reflect the latest GOV.UK wording. (gov.uk)
The communications material indicates a broader compliance push as the first quarterly deadline approaches. HMRC says it has already issued a news release on the approaching deadline and refreshed stakeholder campaign assets. It then plans direct reminders for participants: customers who signed up from April 2026 and miss the first quarterly update deadline on 7 August 2026 are due to receive reminder letters from October 2026, with up to two digital reminders for those using online communications. (gov.uk) That activity will also reach taxpayers who have not yet joined the service. HMRC says customers submitting a 2025 to 2026 Self Assessment return with qualifying income above £30,000 will see an in-service message that their reporting method is changing, and from autumn 2026 the department plans awareness letters to the same income group in phases through to early 2027. HMRC also says customer and agent helplines have been enhanced with updated recorded messages, stronger signposting and an SMS service linking callers to guidance. (gov.uk)
Taken together, the July newsletter reads as a delivery update for a live tax digitisation service rather than a fresh policy announcement. The immediate tasks for developers are clear: complete migration work before the October API retirements, tighten handling of quarterly obligations and onboarding errors, and prepare support teams for higher contact volumes as HMRC’s reminder and awareness activity expands. HMRC has scheduled its next Technical Forum for 8 September 2026 and the next newsletter for 28 August 2026. (gov.uk)