The USCCB’s Committee on Canonical Affairs has issued modifications regarding the celebration of the Solemnity of the Immaculate Conception of the Blessed Virgin Mary, the Patronal Feast Day of the United States. Because the December 8 feast day coincides with the Second Sunday of Advent, it was originally transferred to Monday, December 9, and the requirement to attend Mass was initially lifted. However, recent updates from the USCCB this October indicated that the Solemnity of the Immaculate Conception on Monday, December 9, 2024, will now be recognized as a holy day of obligation. These changes have not yet been reflected in the USCCB’s 2024 and 2025 Liturgical Calendars as of October 29, 2024.