Clarification of the 2007 letter of Pope Benedict XVI to bishops on the liturgy

The following excerpt was copied and pasted from the following webpage on the *Corpus Christi Watershed* website: [More on the subject of “Mutual Enrichment”](https://ccwatershed.org/2020/06/23/more-on-the-subject-of-mutual-enrichment/) : > **A letter of Pope Benedict XVI to bishops, given at Saint Peter’s (7 July 2007), said:** > > > “The two Forms of the usage of the Roman Rite can be mutually enriching: new Saints and some of the new Prefaces can and should be inserted in the old Missal. The ECCLESIA DEI COMMISSION, in contact with various bodies devoted to the *usus antiquior*, will study the practical possibilities in this regard. The celebration of the Mass according to the Missal of Paul VI will be able to demonstrate, more powerfully than has been the case hitherto, **the sacrality which attracts many people to the former usage**. The most sure guarantee that the Missal of Paul VI can unite parish communities and be loved by them consists in its being **celebrated with great reverence** in harmony with the liturgical directives. This will bring out the spiritual richness and the theological depth of this Missal.” I am curious what was meant by the first sentence: "The two Forms of the usage of the Roman Rite can be mutually enriching: ... some of the new Prefaces can and should be inserted in the old Missal." What was meant by "some of the new Prefaces" - I rarely attend the new mass, but when I do, I have not noticed any "preface" lacking from the old.