News for software developers – 4/2025

New version of Ilmoitin.fi has released on 23 September 2025

Key changes:

• You can check and submit self-employed businesses’ income tax returns (Forms 2, 2Y, 2C, 5, 6A, 7K) for tax year 2025.
• Direct transfers of withholding data for 2026
  • You can check and submit:
    • direct transfers of resident pension recipients (VKESSELE)
    • direct transfers of non-resident pension recipients (RVKSSELE)
    • direct transfers of withholding data on wages (VKESSPAE) and
    • data on YEL and MYEL work income (VKTYOSVA) for purposes of the 2026 preassessment.
  • The example materials on the Ilmoitin/IT Developers site have been updated
• The Check feature and the process of having very large files checked
  • The Check (of submitted records) will now require login. This means that users need to identify themselves through Suomi.fi before checking the records. However, no changes were made to the way the Check feature works: for example, there is no requirement for obtaining any authorisations, and like before, Ilmoitin.fi will not send any of the checked files to the Tax Administration.
  • There will now be a background process for files that are large (file size exceeds 10MB when ready for submittal), and this means that the Check feature can no longer be used for instant checking of the records.
• KELA / eSARA
  • Kela will stop accepting eSARA files sent through the Ilmoitin.fi service on 30 September 2025.
  • Kela recommends that all employers who use eSARA files to apply for Kela benefits should start using other e-services instead as soon as possible.
    • The Incomes Register is recommended for large employers,
    • while smaller employers can use either the Incomes Register or the daily allowance and reimbursement service for employers.
  • Read more about the change.
• FATCA
  • The permissible values of “IssuedBy”, when submitting FATCA / AccountHolder/Individual/TIN abd SubstantialOwner/Individual/TIN numbers, will include other country codes – not exclusively US, as it has been so far. This change will concern reports to be filed for the 2025 reportable year (the change will go into effect 1 January 2026).
• A changeover of the test environment is scheduled for mid-October.
  • Moving on to a new test environment will cause no interruptions, and will not require any action on the taxpayer’s or filers’ part.
  • The test environment database will be cleared, so previously submitted test files will no longer appear in the Archive.
• Preliminary plans for changing the Production environment are outlined for end of November or beginning of December.
  • Production environment changeover necessitates downtime for an entire weekend. More precise dates and downtime scheduling will become known later in September.
• No updates to Ilmoitin.fi are planned for the month of November, because at that time we will focus on the Production environment’s planned changes and updates.

News about Vero API

Vero API Call Header Requirements

The firewall rules for the test interfaces (apitest.vero.fi) were tightened on Monday, May 12, 2025, making header information mandatory for all users.

The requirement for Vero API header information in production (api.vero.fi) became mandatory on September 17, 2025. Every Vero API request must include the following general header fields: User-Agent, Content-Type, and Accept.

After this change, the interfaces will return an HTTP 400 error response if a required header is missing, for example: ErrorCode:1005, ErrorText: Missing HTTP Header: User-Agent.

Read more: Technical Guidelines for Vero API Interfaces - vero.fi

Withholding Percentage Request – notification service

On September 17, a new extension was released for the push notification service, enabling the subscription to tax card notifications. From now on, tax card updates can also be received in software systems as push notifications.

The purpose of the extension is to improve the handling of tax card data in software. With this update, payroll processors—such as companies and accounting firms—can subscribe to notifications about employees’ new tax cards and respond automatically by retrieving them via the tax card query API. This eliminates the need for continuous polling and enables real-time reactions only when tax card data changes.

The benefits of the service are significant: it reduces the number of API calls, speeds up processing, saves resources, and improves data accuracy.

Read more on the Finnish Tax Administration’s website: Withholding Percentage Request – notification service

Upcoming changes to the following Vero API interfaces on 17 November 2025

• Changes related improvements to the payment process in the Balance specification and
• Payment reference inquiry APIs
• New Send attachment API
• UsedVehicle v3 API

The documentation for these APIs will be updated in the API Portal on 17 November 2025

Submit your contact details for stakeholder cooperation

Have you noticed that software developers can register to participate in the Finnish Tax Administration’s software development collaboration via the vero.fi website?

Through the page, you can submit and update your contact information for potential collaboration. The contact information will be used for guidance and other communication targeted at software developers.

Submit your contact details here: Software development cooperation - vero.fi

Software developers – events

“Clinics” on Teams (in Finnish)

For 2025, there is an updated schedule for upcoming events on Teams, which you can find on Tilaisuudet - vero.fi on our website.

Our “clinic” style events will offer IT developers a wide variety of information updates. If you have questions or suggestions for issues to be discussed at the next “clinic”, you are welcome to send e-mail to ohjelmistotalot(at)vero.fi – for subject, write: Klinikka.

The Tax Administration and software developers collaboration day online (in Finnish)

The Tax Administration and software developers autumn collaboration day online on November 25, 2025. The day will start at 9:00 AM.

The day will feature current presentations on changes in taxation and their impact on software development. The day's presentations and a detailed schedule will be published closer to the event.

Register for the day (in Finnish)

How to contact us or make enquiries

ohjelmistotalot(at)vero.fi

You can use the e-mail address of the Tax Administration (for software houses) to ask questions related to the Incomes Register as well. We forward the questions to the Incomes Register Unit. However, we remind all users that our e-mail is:

• Intended for those who work with IT development at commercial software vendor companies
• Designed to give guidance and support to IT development
• Not at all for error processing
• Instead, if you detect an error or become aware of a technical problem, always use the observation form to inform the Incomes Register Unit of it.