diff --git a/admin/environment.xml b/admin/environment.xml
index 8f17d3bf3fd..c0ab3d811a3 100644
--- a/admin/environment.xml
+++ b/admin/environment.xml
@@ -122,6 +122,11 @@
           <ON_CHECK message="xmlrpcrecommended" />
         </FEEDBACK>
       </PHP_EXTENSION>
+      <PHP_EXTENSION name="ctype" level="optional">
+        <FEEDBACK>
+          <ON_CHECK message="ctyperecommended" />
+        </FEEDBACK>
+      </PHP_EXTENSION>
     </PHP_EXTENSIONS>
   </MOODLE>
   <MOODLE version="1.9">