EDLD 5344- School Law

I'm taking my 3rd master's class (in Administration).  There are many things to learn.  I have heard of Section 504 and IDEA (now IDEIA), but didn't know that there have been ammendments to them. And  this is my 6th year to teach.  Where is the lack of communication coming from?  If I'm required to follow the laws (IEPs are a legal document), shouldn't it be a requirement to let teachers know when something has changed?  I'm feeling a little frustrated at this point.