diff --git a/chrome/content/mailhops.js b/chrome/content/mailhops.js
index 43ca84d..05bdb98 100644
--- a/chrome/content/mailhops.js
+++ b/chrome/content/mailhops.js
@@ -9,7 +9,7 @@ var mailHops =
   msgURI:	null,
   isLoaded: false,
   options: {
-      'version':'MailHops Plugin 3.1.7',
+      'version':'MailHops Plugin 3.1.8',
       'lan':'en',
       'unit':'mi',
       'api_http':'https://',
@@ -37,7 +37,6 @@ mailHops.LOG = function(msg) {
 };
 
 mailHops.init = function() {
-
   //load preferences
   mailHops.loadPref();
 
@@ -330,7 +329,11 @@ mailHops.setupEventListener = function(){
 mailHops.registerObserver = function(){
   var prefService = Components.classes["@mozilla.org/preferences-service;1"].getService( Components.interfaces.nsIPrefService ) ;
   mailHops._branch = prefService.getBranch( "mail.mailHops." ) ;
-  mailHops._branch.QueryInterface( Components.interfaces.nsIPrefBranch ) ;
+  try {
+    mailHops._branch.QueryInterface( Components.interfaces.nsIPrefBranchInternal ) ;
+  } catch (err){
+    mailHops._branch.QueryInterface( Components.interfaces.nsIPrefBranch ) ;
+  }
   mailHops._branch.addObserver( "" , mailHops , false ) ;
 };
 
diff --git a/install.rdf b/install.rdf
index 340bc80..5fd002a 100644
--- a/install.rdf
+++ b/install.rdf
@@ -5,7 +5,7 @@
 	<Description about="urn:mozilla:install-manifest">
 		<em:type>2</em:type>
 		<em:id>thunderbird@mailhops.com</em:id>
-		<em:version>3.1.7</em:version>
+		<em:version>3.1.8</em:version>
 
 		<em:name>MailHops</em:name>
 		<em:description>MailHops maps the route an email took to get to you. Displaying the senders location, weather, user-agent and authentication used.</em:description>