Belariath

Question:

When upgrading to an advanced class, do that class's weapon and armor restrictions override the original class's restrictions?
For instance, if I start with a mage (weapon and armor class A) and then upgrade to one of the elemental classes (weapon and armor classes A,B), will I then be allowed to use B-class items? Or do I have to upgrade from a starting class that doesn't have A-class restrictions?

Thanks in advance.

The Advanced Class will override what used to be your starting class.

Thanks