diff --git a/developers.html b/developers.html
index ff72020dacd06cf428a1328327da8d047077166a..17c9efb6440682f49d81f2564527a5daf450ffb4 100644
--- a/developers.html
+++ b/developers.html
@@ -2386,7 +2386,8 @@ netbeans_jdkhome="C:\Program Files\Java\jdk1.8.0_221"</pre>
       </p>
       <ul>
           <li>
-              <a href="http://tomcat.apache.org" target="_blank">Apache Tomcat</a> official release site.
+              <a href="https://tomcat.apache.org" target="_blank">Apache Tomcat</a> official release site with
+              <a href="https://tomcat.apache.org/tomcat-9.0-doc/index.html" target="_blank">Apache Tomcat 9.0 User Guide</a>.
           </li>
           <li>
               <a href="https://en.wikipedia.org/wiki/Apache_Tomcat" target="_blank">Wikipedia: Apache Tomcat</a>
@@ -2401,6 +2402,24 @@ netbeans_jdkhome="C:\Program Files\Java\jdk1.8.0_221"</pre>
               <a href="https://datacadamia.com/tomcat/logon" target="_blank">Datacadamia: how to log in</a> includes configuration guidance.
           </li>
       </ul>
+      <p>
+          Developer notes:
+      </p>
+      <ul>
+          <li>
+              Local installation as regular user (rather than local administrator) can simplify Tomcat configuration and access.
+          </li>
+          <li>
+              Ensure that <code>CATALINA_HOME</code> points to root directory of current Tomcat installation.
+          </li>
+          <li>
+              Troubleshooting in progress: not working in Netbeans&nbsp;12.3, backtracking to Netbeans&nbsp;12.2 and OpenJDK&nbsp;14.02, 
+              still no joy...
+          </li>
+          <li>
+              No plans yet to upgrade to Tomcat&nbsp;10 since package and class invocation is different.
+          </li>
+      </ul>
       <p>
           Example information for <i>conf/tomcat-users.xml</i> configuration file follows.
           Note that any username must also be configured in the Tomcat installation itself.
@@ -2414,10 +2433,7 @@ netbeans_jdkhome="C:\Program Files\Java\jdk1.8.0_221"</pre>
 
 &lt;user username="moi" password="no-really" roles="admin,admin-gui,admin-script,manager-gui,manager-script" /&gt;
 </pre>
-      <p>
-          Under Windows operating system, better results have been obtained when installing Tomcat as local user
-          rather than requiring administrator permissions.
-      </p>
+
       <!-- =========================================================== -->
 
       <h2>
@@ -2999,7 +3015,7 @@ which can lead to the Internet of Things becoming the Web of Things. </i>
             <a href="https://savage.nps.edu/developers.html">https://savage.nps.edu/developers.html</a>
         </blockquote>
         <blockquote>
-            Revised 6 May 2021.
+            Revised 13 May 2021.
         </blockquote>
 
         <p>