Are Canonisations Infallible?
Dogmatic definitions never involve a new doctrine of faith or morals, since whatever a Pope defines must be contained in Holy Writ or in Tradition in order to be infallible.
Pope Saint Paul VI (3 April 1969): “Although the text of the Roman Gradual—at least that which concerns the singing—has not been changed, the Entrance antiphons and Communions antiphons have been revised for Masses without singing.”