Update SotD to mention implementation requirements during CR.

index.html

@@ -259,8 +259,13 @@
 
     <section id='sotd'>
       <p>
-This is an experimental specification and is undergoing regular revisions. It
-is not fit for production deployment.
+The Working Group is actively seeking implementation feedback for this
+specification. In order to exit the Candidate Recommendation phase, the
+Working Group has set the requirement of at least two independent
+implementations for each mandatory feature in the specification. For details
+on the conformance testing process, see the test suites listed in the
+<a href="https://w3c.github.io/vc-data-integrity/implementations/">
+implementation report</a>.
       </p>
     </section>