FERIAE IN IUDICIIS. - On certain days of the year procedural acts may not be performed. These dies feriati or feriae are divided: 1) into ordinary, established exhaustively in the CIC (can. 1639: holydays of obligation and the last three days of Holy Week), and extraordinary, established by the competent authorities for special events (anniversaries of the election of the Pontiff, of the Lateran Pacts, etc.); and 2) into iuris communis (established for the whole Church) and iuris particularis (established by the individual ordinaries, can. 1638 § 1).
Unlike that of the Decretals, current law considers procedural acts performed on ferial days merely unlawful, but not invalid. In individual cases required by necessity, Christian charity, and the public good, can. 1639 permits the judge to perform such acts on ferial days; normally, however, under can. 1635, there is a de iure extension to the next first non-ferial day.