Today is Ember Friday in Advent. It ranks as a greater, non-privileged ferial day.
At Mattins the lessons are a homily from St. Ambrose of Milan on St. Luke's account of the Visitation. From the 17th December, yesterday, there are sets of proper antiphons to be sung at Lauds and the Hours.
These six sets of antiphons, five in the old Roman Breviary, are used on the weekdays before Christmas Eve. Yesterday, being Thursday, had the set De Sion etc. Today the set Constantes estote are sung. The second scheme of Lauds is sung (the traditional ferial Lauds in the old Breviary) and the 'kneeling prayers', the preces feriales are sung before the collect of the Ember Friday. The antiphon on the Benedictus is proper.
At the Hours these special antiphons are sung in sequence. The short set of preces feriales are sung at each hour (a longer set at Prime) with those in choir kneeling.
Mass is sung after None. The ministers wear folded chasubles. The Mass texts are proper, the collect is another of the Excita series. The second collect is of the BVM, Deus, qui de beate and the third for the Church, Ecclesiae. The dismissal is Benedicamus Domino.
At Vespers the antiphon on the Magnificat is O Adonai. (In England, traditionally, O radix Jesse). The Great 'O' Antiphons are unique in the ferial Office in that they are doubled. i.e. sung in their entirety both before and after the Canticle, and sung with the choir standing. Again the preces feriales are sung, kneeling, at Vespers too. The collect is from the Sunday, the Ember Friday liturgy ending with the Mass after None. At Compline the preces are also sung whilst kneeling.