diff --git a/toolkit/mozapps/update/src/nsUpdateService.js.in b/toolkit/mozapps/update/src/nsUpdateService.js.in
index fbaba51e627..6a1650dd720 100644
--- a/toolkit/mozapps/update/src/nsUpdateService.js.in
+++ b/toolkit/mozapps/update/src/nsUpdateService.js.in
@@ -1372,7 +1372,7 @@ UpdateService.prototype = {
              getService(Ci.nsIVersionComparator);
     for (var i = 0; i < updates.length; ++i) {
       // Ignore updates for older versions of the application
-      if (vc.compare(updates[i].version, gApp.version) < 0)
+      if (vc.compare(updates[i].extensionVersion, gApp.version) < 0)
         continue;
       if (updates[i].type == "major" &&
           vc.compare(newestMajor.version, updates[i].version) <= 0)
@@ -1804,9 +1804,9 @@ UpdateService.prototype = {
              getService(Ci.nsIVersionComparator);
     // Don't download the update if the update's version is less than the
     // current application's version.
-    if (update.version && vc.compare(update.version, ai.version) < 0) {
+    if (update.extensionVersion && vc.compare(update.extensionVersion, ai.version) < 0) {
       LOG("UpdateService", "downloadUpdate - removing update for previous " +
-          "application version " + update.version);
+          "application version " + update.extensionVersion);
       cleanupActiveUpdate();
       return STATE_NONE;
     }
diff --git a/toolkit/mozapps/update/test/unit/test_0020_general.js b/toolkit/mozapps/update/test/unit/test_0020_general.js
index bf451f8de8a..cb493c9705e 100644
--- a/toolkit/mozapps/update/test/unit/test_0020_general.js
+++ b/toolkit/mozapps/update/test/unit/test_0020_general.js
@@ -249,13 +249,13 @@ function run_test_pt10() {
                                   "e6678ca40ae7582316acdeddf3c133c9c8577de4",
                                   "1316138");
   var updates = getRemoteUpdateString(patches, "XPCShell App Update Test",
-                                      "minor", "1.0pre", "2.0",
-                                      "3.0", "20080811053724",
+                                      "minor", "version 1.0pre", "2.0",
+                                      "1.0pre", "20080811053724",
                                       "http://dummylicense/index.html",
                                       "http://dummydetails/index.html");
   updates += getRemoteUpdateString(patches, "XPCShell App Update Test",
-                                   "minor", "1.0a", "2.0",
-                                   "3.0", "20080811053724",
+                                   "minor", "version 1.0a", "3.0",
+                                   "1.0a", "20080811053724",
                                    "http://dummylicense/index.html",
                                    "http://dummydetails/index.html");
   gResponseBody = getRemoteUpdatesXMLString(updates);
@@ -278,8 +278,8 @@ function run_test_pt11() {
                                   "e6678ca40ae7582316acdeddf3c133c9c8577de4",
                                   "1316138");
   var updates = getRemoteUpdateString(patches, "XPCShell App Update Test",
-                                      "minor", "1.0", "2.0",
-                                      "3.0", "20080811053724",
+                                      "minor", "version 1.0", "3.0",
+                                      "1.0", "20080811053724",
                                       "http://dummylicense/index.html",
                                       "http://dummydetails/index.html");
   gResponseBody = getRemoteUpdatesXMLString(updates);
@@ -290,6 +290,6 @@ function run_test_pt11() {
 function check_test_pt11() {
   var bestUpdate = gAUS.selectUpdate(gUpdates, gUpdateCount);
   do_check_neq(bestUpdate, null);
-  do_check_eq(bestUpdate.version, "1.0");
+  do_check_eq(bestUpdate.version, "version 1.0");
   end_test();
 }