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New version of to be launched 6 February 2024


From 7 am to 9 am on 6 February 2024, service is down and both the website and its software interfaces are temporarily unavailable.

Key changes:

  • accepts income tax returns for corporate taxpayers 2024 accounting periods. Users can both check and submit returns (Forms 4, 6, 6B, 6C and 6U).
    • In addition to the annual changes, there have been other changes to the following data format specifications: 4, 6, 6B, 6C, 6U, 8A, 67Y, 74, 81, VSYENN
    • Attachment type "Tilinpaatos" changed to "Vahvistettu tilinpaatos".
    • New attachment type: "Voitonjakotiedot kaupparekisteriin"
    • Data format specifications are available on
  • Changes to background checking:
    • If a user submits multiple files and even one of them is larger than 5 MB (or 1 MB for XML files), they will now be given the option to submit them to background processing.
    • Due to data security concerns, error codes have been removed from the e-mail sent to the user after the checking has been completed. Users can view the errors on as follows:
      • If the filing was submitted while logged in: go to "Archive", select "Large filings for background checking", and click "Errors".
      • If the filing was submitted via the background checking functionality without logging in, the file containing errors must be checked again without submitting it to background processing: go to "Submit for background checking" and select "I want to launch the check process immediately".
  • The data format specifications for annual information returns for the 2024 reporting year are published on 5 February, but their formats will not be available until the March version of is launched on 26 March 2024. The specifications are available on