Fixed typo, updated test

README.rst

@@ -54,6 +54,12 @@ run the following command::
 
   $ ./run.py --stop-after-configfile-check <your domain>
 
+If you updated your installer, your config file might be outdated.
+The program will exit after the update, so you can check the config file
+before continuing. To perform the update, run the following command::
+
+  $ ./run.py --update-configfile <your domain>
+
 An interactive mode is also available::
 
   $ ./run.py --interactive <your domain>