diff --git a/mozilla/toolkit/mozapps/update/src/nsUpdateService.js.in b/mozilla/toolkit/mozapps/update/src/nsUpdateService.js.in
index 9ca3b40e82e..45362e79fe5 100644
--- a/mozilla/toolkit/mozapps/update/src/nsUpdateService.js.in
+++ b/mozilla/toolkit/mozapps/update/src/nsUpdateService.js.in
@@ -53,7 +53,6 @@ const PREF_APP_UPDATE_URL_DETAILS         = "app.update.url.details";
 const PREF_APP_UPDATE_CHANNEL             = "app.update.channel";
 const PREF_APP_UPDATE_SHOW_INSTALLED_UI   = "app.update.showInstalledUI";
 const PREF_APP_UPDATE_LASTUPDATETIME_FMT  = "app.update.lastUpdateTime.%ID%";
-const PREF_APP_EXTENSIONS_VERSION         = "app.extensions.version";
 const PREF_GENERAL_USERAGENT_LOCALE       = "general.useragent.locale";
 const PREF_APP_UPDATE_INCOMPATIBLE_MODE   = "app.update.incompatible.mode";
 const PREF_UPDATE_NEVER_BRANCH            = "app.update.never."