Product update – Version 2021.3


  • CT600 (2021) Version 3 and CT600L supplementary page
  • Administrator rights change

Bug fixes:

  • Taxonomy update for periods ending after 04/2021
  • SA104 Partners loss and SEISS grant online filing error
  • Debtors note

CT600 update:

The CT600L is required for all claims to Research & Development tax credits for any period when submitting both amended and new CT600 returns to HMRC.

If you have an existing claim to Research & Development credits you will need to access the data entry section and click on Save changes to ensure the correct CT600 and CT600L is generated as expected

The updated version of the CT600 includes several changes:

New boxes 471 – 474 & 647 to report Coronavirus Support Scheme payments and overpayments

HMRC have made changes to the population of Research & Development tax credits boxes in the Tax reconciliation section on page 6 of the CT600 (2021) Version 3 that differs from previous versions of the tax return.

  • Box 530 – the amount of Research & Development credit no longer includes the full amount of the payable credits but is now:
    • Research & Development tax credit set off against other liabilities arising in the Return period such as tax on Loans to Participators 
    • Research & Development Expenditure Credit used to discharge the Corporation Tax liability and amounts set off against other liabilities arising in the Return period such as tax on Loans to Participators 
  • Box 570 – As a result of the limit to the values now being shown in box 530, box 570 will no longer show payable Research & Development credits.
  • Box 605 – as a direct result of the changes to the previous boxes any overpayment arising from the claim to a payable tax credit will no longer appear in this box. The payable tax credits continue to be shown in boxes 875 and 885.
HMRC Exclusion from Filing CT600L online

Please note that where a claim to Research & Development Expenditure credit includes an amount of Step 2 notional tax charge restriction brought forward or Expenditure credit brought forward from a previous period this cannot be filed online due to an HMRC system error. Taxfiler will advise when these exclusions are triggered. The correct CT600L including the brought forward values will be produced together with a detailed report of the full claim in the associated computation allowing for the correct paper submission to be made. When sending the completed return to HMRC please ensure you attach a completed WT1 form. 

Research & Development – outstanding functionality in Taxfiler

In ensuring there no additional delays to this release there are some outstanding areas of functionality that could not be included. The following areas will be addressed as soon as possible in a later release:

  • Roll forward of carried forward amounts in the new Above The Line data entry screen within the Research & Development section – the Step 2 notional tax restriction and the Step 3 expenditure credit carried forward will not be automatically rolled forward to later periods.    

Administrator rights:

An administrator can add users and allocate a license to users. An administrator is not able to remove a licence from a user this will need to be done by the primary user.

Bug fixes:

Taxonomy error:

The fix for the following error has been implemented. “The submission of this document has failed due to departmental specific business logic in the Body tag. The period to which this Return’s Accounts applies does not coincide with the effective from/to dates of the referenced Accounts Taxonomy. Please correct and re-submit”

Users who received this error will need to remove the accounts from the tax return and re-attach them before trying to submit again. If the return is locked please follow the process to unlock as described here.


The amount of SEISS is not correctly taken into the calculation of Adjusted profit/(loss), was causing an online filing error, this has been corrected.

Debtors note:

Update to the formatting of the debtors note has been included