Normative vs. Non-Normative Text

In order to distinguish normative text, which contains requirements for implementers from non-normative text, which is usually background or helpful but not complusory material, sections or subsections of the text should be marked as normative or non-normative.

That is usually announced in 1.2 Terminology by saying:

**All notes and examples in this specification and any section marked as "Non-Normative," are non-normative. All other text is normative.**

Or words to that effect.

After inserting that language, review the draft for sections that should be marked as non-normative, such as 2.1 Introduction for example. 2.3.1 is another. Are any of the appendixes normative?

**************************************

After looking more closely at 2.3.1 I think I am wrong about it being non-normative. There are keywords (MUST, MAY) so it should be normative.

***************************************

I just discovered under 4 Supported Message Exchange Standards, last paragraph, that:

"Section 4.5 is non-normative, as the current version of the specification it references is a working draft."

Using the labeling mechanism would handle this case.