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Guidance

Edition 1: Making Tax Digital for Income Tax — software developer newsletter

Published 29 May 2026

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This publication is available at https://www.gov.uk/government/publications/edition-1-making-tax-digital-for-income-tax-software-developer-newsletter/edition-1-making-tax-digital-for-income-tax-software-developer-newsletter

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

This edition of the newsletter includes:

  • API status updates
  • new API releases
  • live service issues
  • updates on guidance and communications

API deprecation and retirement update

API status summary

To help you stay aligned with the latest MTD for Income Tax API changes, the table below provides an update on API versions approaching retirement.

API Version Status Deprecation date Retirement date Required action
business-details-api V1 deprecated 16 October 2025 16 April 2026 upgrade to V2
individual-calculations-api V7 deprecated 16 October 2025 16 April 2026 upgrade to V8

Important notes for developers

HMRC have already contacted software providers who are still subscribed to these API versions, to make them aware of the upcoming retirement dates and encourage them to take action.

Software developers are reminded that:

  • deprecated versions remain available for 6 months before retirement
  • developers cannot subscribe to deprecated versions, new integrations must use the latest available version
  • HMRC recommends upgrading as early as possible to avoid disruption and stay aligned with the MTD for Income Tax API Roadmap

New in the March 2026 API release

The latest API changes and new from the live in production from 24 March 2026 include:

  • quarterly deadlines aligned with VAT — quarterly updates are now due on the 7th of each month (Obligations API v3)
  • foreign property submissions enhanced — submissions are now accepted at individual property level, rather than country level (BSAS v7, Calc v8)
  • Income Tax Self Assessment (ITSA) status terminology updated — ‘non‑digital’ has been renamed to ‘digitally exempt’
  • transition profit fields added —  new ‘transitionProfit’ fields added to the individual calculations API (API v7/v8)
  • new state benefits validation rule — submissions will be rejected if ‘taxPaid’ is included for state benefits, including state pension and Bereavement Allowance (state benefits API v2)

  • Capital Gains enhancements (CG API) — support added for:

    • crypto assets
    • unlisted shares and securities
    • multiple BADR asset types
    • new fields including claim and election codes and RTT Tax Paid

Live service issues — developer update

This section highlights:

  • the most common issues reported by software developers in March
  • guidance to help you resolve these issues quickly
  • an understanding of where HMRC is already taking action

User issues

These are common issues that can usually be resolved without raising a live service issue (LSI).

Issue Developer Action
Authorisation errors Check the customer is signed up for MTD Income Tax Self Assessment (ITSA), the agent is authorised to act for them, and the token you’re using has the right permissions
Early Tax Year 2026 to 2027 calls Avoid calling Tax year 2026 to 2027 endpoints before 6 April — they will not be accepted
Quarter and period alignment Check your quarter dates and confirm ‘taxYearOfChoice’ matches the year you intend to submit for
API availability Some features (especially Tax year 2026 to 2027) may not be live — check the MTD for Income Tax API Change log before calling an endpoint

Live service issues (LSIs)

These issues are known to HMRC or require escalation through the agreed LSI process.

Issue Developer Action
Postcode mismatch Use the customer’s home address postcode — the system now checks against that.
Quarter 1 submission not fulfilled Nothing for you to change — HMRC is resolving this, and it affects only a small number of submissions.
Property income not pre‑populating Let users know they must add property income manually for now.
AIA + cash‑basis restriction annual investment allowance (AIA) can only be claimed at year end while the system defaults to cash basis. If an error appears, users will need to remove the in‑year AIA claim and re‑add it at year‑end.

For the fastest resolution, continue to raise LSIs through your account manager using the makingtaxdigital-softwarevendors@hmrc.gov.uk.

Service updates

Read the latest planned downtime on the API platform status page.

Customer and agent guidance updates

There are three main GOV.UK guidance products available to help users understand and prepare for MTD for Income Tax:

This guidance is kept under review and regularly updated.

Communications update

This section provides an update on recent communications activity related to Making Tax Digital for Income Tax.

MTD customer awareness letters 

HMRC has sent letters to customers who have submitted their 2024‌‌‌ to‌‌‌ 2025 tax return, informing them of their requirement to use Making Tax Digital (MTD) for Income Tax from April‌‌‌ 2026.

Letters were issued in November, February and March, based on when the 2024 to 2025 return was filed (up to 31 January 2026). A final batch will be sent in early June for customers who file after 31 January or submit an amendment.

These letters help prepare customers for MTD for Income Tax and may increase engagement with your software.

You can read a copy of the customer awareness letter.

Agent campaign activity

Highlights of the campaign activity include:

Developer engagement and feedback

Views are welcome on how HMRC guidance could be used more effectively within software products. This could include:

  • linking directly to relevant guidance
  • surfacing content within products
  • using HMRC’s digital assistant
  • walking developers through existing guidance content

Ways to engage and provide feedback include:

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