Is a Form 56 (Notice Concerning Fiduciary Relationship) required to be filed by a Trustee of a Trust?

It looks like I have to file two 56 forms, one for the Decedent and another for the Decedent’s Trust. Is that true? If so, when does it have to be filed by? Will filing them before or at the same time of filing the Deceased taxpayer’s 1040 tax return and the 1041 Trust Tax return meet the filing deadline? Thanks!