St Teresa of Calcutta, canonized in 2016 by Pope Francis, has been assigned a feast day (with the rank of an Optional Memorial) in the Universal Calendar of the Church on 5 September. The new Collect (the opening prayer of the Mass) for St Teresa’s feast day opens for us the heart of her spirituality: the call to satisfy the thirst of Jesus Christ on the Cross by answering with love the needs of the most needy. For this reason, we ask God the Father that, imitating her example, we may minister to Christ present in our suffering brothers and sisters.
See the decree from the Dicastery for Divine Worship here (in Latin; scroll down for other languages.
More from the Dicastery for Divine Worship here.
The texts for the Mass and Divine Office are here in Latin; translations will no doubt follow from ICEL.