The preferred dividends can be cumulative or non cumulative. The non cumulative preferred stock is less frequent and has the same treatment as ordinary stock or in other words, it’s only recognized when declared. If it’s not declared, the company is not liable to pay any dividend.
In the case of the cumulative preferred stock, the dividends in arrears are disclosed in the notes if they are not declared or they are recognized as a current liability if they are approved by the board of directors.