Here we come to the end of this document and it comes by way of the appendix. It concerns a revision of the calendar but probably does not refer to what you think it refers.
The first point of this section states that the Church is not opposed to fixing Easter on a certain Sunday of the Gregorian calendar every year. (Interesting no?) The Council of Nicaea (A.D. 325) set the date of Easter as the Sunday following the paschal full moon, which is the full moon that falls on or after the vernal (spring) equinox. Rather than a floating date, the Church said it would be open to something more stable “provided that those whom it may concern give their assent, especially the brethren who are not in communion with the Apostolic See.” Good luck with that.
There are organizations out there trying to unite the date of Easter between Catholics, Orthodox, and Proetestants. Onedate.org is one of those organizations. I have no idea who sponsors this site (I'm not recommending it, just holding it up as an example.) Isn't it nice to know that our Church is at least open to the idea?
The council also declared that there is no problem if there is going to be a perpetual calendar on society. Not everybody follows the Gregorian calendar and not every calendar sees this year as 2013. The only requirements are that there are 7 day weeks with a Sunday so that the liturgical calendar might be maintained. But even so, with grave reason, some of this might be done away with also.
Who says that they Church isn’t open and flexible?