Are you serious? Vatican II made so many changes it caused schism in the Catholic Church.
Sedevacantism (
Latin:
Sedevacantismus) is a doctrinal position within
traditionalist Catholicism,
[1][2] which holds that the present occupier of the
Holy See is not a
valid pope due to the pope's espousal of one or more
heresies and that therefore, for lack of a valid pope, the
See of Rome is vacant.
The term
sedevacantism is derived from the Latin phrase
sede vacante, which means "with the chair [i.e. of the
Bishop of Rome] being vacant".
[3] The phrase is commonly used to refer specifically to a vacancy of the Holy See from the death, the
resignation, the falling into insanity, or the public heresy of a pope to the
election of his successor.
Among those who maintain that the see of Rome, occupied by what they declare to be an illegitimate pope, was really vacant, some have chosen an alternative pope of their own, thereby in their view ending the vacancy of the see; such are known sometimes as
conclavists.
[4]
The number of sedevacantists is unknown and difficult to measure; estimates range from tens of thousands to hundreds of thousands.
[5]-Wikipedia
And that's just one of the 21. Each one caused schism by those rejecting the new version of Catholicism. Sometimes many rejected the changes, sometimes only a few forgotten by history. But no change was made without dissent.