The accounting policies are changed only if the change:
A change in the accounting policies associated with initial application of IFRS is settled in accordance with specific transitional provisions contained in such IFRS. If a change in accounting policies is made in connection with initial application of IFRS which do not contain specific transitional provisions pertaining to such a change or the change is made voluntarily, the entity introduces such a change retrospectively. Retrospective introduction of a change in the accounting policies is made through a correction in the statement of financial position of the opening balance of each equity item to which the change pertains for the earliest presented period and disclosure of other comparative data for each period, as if the changed accounting policies have been always applied.
The financial statements items determined on the basis of estimates are subject to verification, if the circumstances constituting the basis for the estimates change or as a result of obtaining new information or gathering more experience.
The effects of a change of an estimate value are prospective, which means that the values pertaining to the transactions, other events and conditions are adjusted as of the moment when the change was made (the change influences only the current statement of comprehensive income, or the results of the given period or future periods).
An assumption is made that errors are corrected already in the period in which they were made (not detected), hence material errors from previous periods are corrected retrospectively, and the difference is charged to equity.
In 2020 as well as in 2019, there were not corrections of errors from previous years.