Does St. Gertrude's prayer have any (semi-)official standing in the Catholic Church? I'd like to know if there was any official or unofficial statement given by the Roman Catholic Church on the St. Gertrude's prayer that saves 1000 souls from purgatory?

Is there even any record from her biography that she received this prayer and information that the prayer has this power?

Source
Prayers that are supposed to automatically release souls from purgatory are "declared to be apocryphal" (i.e. false) and are prohibited, according to the Acts of the Holy See 32 p.243, as promulgated by Pope Leo XIII.


  Reiicienda sunt folia, et libelli, in quibus promittitur fidelibus unam alteramve precem recitantibus liberatio unius vel plurium animarum a Purgatorio : et Indulgentiae quae dictae promissioni adiici solent ut apocryphae habendae sunt.


Translation


  The leaflets and booklets which promise the faithful that they will free one or more souls from Purgatory by the recitation of some prayer or another are to be rejected : and the Indulgences which are wont to be attached to the said promise are to be held as apocryphal.