Plenary Indulgence reminder: Te Deum:

(26) § 1. A plenary indulgence is granted to the Christian faithful who, in a church or in an oratory, are present [take part] in a recitation or solemn chant of:

2° the Te Deum hymn, on the last day of the year, in thanksgiving to God for the favors received in the course of the entire year.

(Reference: Enchiridion Indulgentiarum, 4th edition, al. concessiones.(Rorate Caeli: here)