Optional Rules?

[KirkH]

I was perusing the V4 rules to see if the Fog-of-War optional rule had changed, but I don't see the optional rules anywhere.  The V4 rules reference FOW and other optional rules, but I don't see the optional rules at the end like they used to be.  It made me start looking for other V3 rules such as hidden units and overruns and I don't see those anymore either.  What happened to those rules?  Are they not allowed in V4?