Version & is still being used as a valuation version (&/&/&)

What causes this issue?

You want to delete version &V1&. Version &V1&, however, is still being
used as a valuation version (controlling area &V2&, version &V3&,
fiscal year &V4&).

Procedure for System Administrators

Go to the settings for controlling area &V2&, version &V3& in fiscal
year &V4&. Choose the detail screen. Version &V1& is entered as
valuation version IAA for orders/projects. Delete this entry.

Error message extract from SAP system. Copyright SAP SE.