The Church does not encourage devotions related to the Divine Mercy chaplet, other Divine Mercy prayers, or the use of Divine Mercy imagery. Neither does the Church observe Divine Mercy Sunday.
The Church does not consider Faustina Kowalska, the originator of the Divine Mercy devotions, to be a saint.
Parishes, institutes or ministries affiliated with the Church should not sponsor any devotions or services related to “Divine Mercy,” including the reading of Faustina Kowalska’s writings.
Detailed information is available in an article “Church Reasons to Condemn the Divine Mercy Devotion” on an unaffiliated website.