any change in the fundamental beliefs or doctrine?
You might already know this but I'll say it anyway; when you think of the belief system in the Church think 3 Ds: dogma, doctrine, and discipline.
Dogma cannot be changed. This is where infallible declarations are made from the seat of Peter.
Doctrine is based on dogma. The way I understand doctrine is that it fundamentally cannot be changed but is up for some interpretation. Think of cannon law and the liturgy as examples.
Discipline is base on doctrine (sacred scripture and Tradition) but can be changed by the local bishop. An example of discipline in the Latin rite is priestly celibacy. Other catholic rites don't practice this discipline. BTW, the practice is biblical first suggested by St. Paul.
ETA, in summary changes in the Church go like this:
Dogma - No.
Doctrine - ehhh, maybe
Discipline - Yes (but very slowly, lol)
This post was edited on 3/13 at 9:35 pm