Specify docs with undefined terms MUST include related context.

index.html

@@ -3216,10 +3216,15 @@ <h4>Semantic Interoperability</h4>
           </p>
 
           <p>
-Developers SHOULD NOT use the <a data-cite="JSON-LD11/#default-vocabulary">`@vocab`</a> feature in production as it can lead to
-JSON term clashes, resulting in semantic ambiguities with other applications. Instead,
-to achieve proper interoperability, developers SHOULD define all terms used by their
-applications, as described earlier in Section [[[#extensibility]]].
+A [=conforming document=] SHOULD NOT use the
+<a data-cite="JSON-LD11/#default-vocabulary">`@vocab`</a> feature in production
+as it can lead to JSON term clashes, resulting in semantic ambiguities with
+other applications. Instead, to achieve proper interoperability, a [=conforming
+document=] SHOULD use JSON-LD Contexts that define all terms used by their
+applications, as described earlier in Section [[[#extensibility]]]. If a
+[=conforming document=] does not use JSON-LD Contexts that define all terms
+used, it MUST include the `https://www.w3.org/ns/credentials/undefined-terms/v2`
+as the last value in the `@context` property.
           </p>
         </section>
       </section>