Edit: this was published at Rorate.
Benedictus XVI
Papa emeritus
Città del Vaticano10-10-2014Most honorable Delegate-General,
I have at last found the time to thank you for your letter of the past August 21. I am very glad that theUsus antiquus now lives in full peace within the Church, also among the young, supported and celebrated by great Cardinals.
I will be spiritually with you. My state as a 'cloistered monk' does not allow me a presence that is also exterior. I leave my cloister only in particular cases, [when] personally invited by the Pope.
In communion of prayer and friendship.
Yours in the Lord,Benedict XVI