See updates to this report below: 

March 13: The Holy See has yet to release the full text of the letter Pope Emeritus Benedict XVI sent to Msgr. Dario Vigano, the prefect of the Secretariat for Communications, on 11 short books on The Theology of Pope Francis, but it has now been published this afternoon by Sandro Magister on his blog, Settimo Cielo. (It later emerged this was not the full text which the Vatican eventually published on March 17 — see details below).