Explain why GnuPG cannot update all keys from Hagrid.

dist/templates/about/faq.html.hbs

@@ -87,5 +87,23 @@
     <p>We do plan to explore options for a distributed service in the future, so
         users can choose between different service operators again.
     </p>
+
+    <h3 id="older-gnupg"><a href="#older-gnupg">
+	I have trouble updating some keys with GnuPG.  Is there a bug?
+    </a></h3>
+
+    <p>
+      This is a problem with current versions of GnuPG.  If you are
+      trying to update a key whose owner has not opted-in to having
+      their userid(s) published, GnuPG will complain complain about
+      the key having no userid:
+    </p>
+    <blockquote>
+      $ gpg --receive-keys FB3751F1587DAEF<br>
+      gpg: key FB3751F1587DAEF1: no user ID
+    </blockquote>
+    <p>
+      We are working with the GnuPG team to resolve this problem.
+    </p>
 </div>
 {{/layout}}

dist/templates/about/usage.html.hbs

@@ -45,7 +45,11 @@
             <blockquote>gpg --auto-key-locate keyserver --locate-keys user@example.net</blockquote>
         </li>
         <li>To refresh all your keys (e.g. new revocation certificates and subkeys):
-            <blockquote>gpg --refresh</blockquote>
+            <blockquote>gpg --refresh-keys</blockquote>
+	    <b>Note:</b> If you see messages like the following,
+	    see <a href="faq#older-gnupg">here</a> for notes on
+	    compatibility with older versions of GnuPG.
+	    <blockquote>gpg: key FB3751F1587DAEF1: no user ID</blockquote>
         </li>
     </ul>