diff --git a/randomwallpaper@iflow.space/elements.js b/randomwallpaper@iflow.space/elements.js
index 4558e5e..8217b8f 100644
--- a/randomwallpaper@iflow.space/elements.js
+++ b/randomwallpaper@iflow.space/elements.js
@@ -14,7 +14,7 @@ const Self = imports.misc.extensionUtils.getCurrentExtension();
 const LoggerModule = Self.imports.logger;
 const Timer = Self.imports.timer;
 
-const HistoryElement = new Lang.Class({
+var HistoryElement = new Lang.Class({
 	Name: 'HistoryElement',
 	Extends: PopupMenu.PopupSubMenuMenuItem,
 	logger: null,
@@ -150,7 +150,7 @@ const HistoryElement = new Lang.Class({
 	}
 });
 
-const CurrentImageElement = new Lang.Class({
+var CurrentImageElement = new Lang.Class({
 	Name: 'CurrentImageElement',
 	Extends: HistoryElement,
 
@@ -170,7 +170,7 @@ const CurrentImageElement = new Lang.Class({
  *
  * @type {Lang.Class}
  */
-const NewWallpaperElement = new Lang.Class({
+var NewWallpaperElement = new Lang.Class({
 	Name: 'NewWallpaperElement',
 	Extends: PopupMenu.PopupBaseMenuItem,
 
@@ -221,7 +221,7 @@ const NewWallpaperElement = new Lang.Class({
 	}
 });
 
-const StatusElement = new Lang.Class({
+var StatusElement = new Lang.Class({
 	Name: 'StatusElement',
 	Extends: St.Icon,
 
diff --git a/randomwallpaper@iflow.space/extension.js b/randomwallpaper@iflow.space/extension.js
index 6344f7d..bf577bd 100644
--- a/randomwallpaper@iflow.space/extension.js
+++ b/randomwallpaper@iflow.space/extension.js
@@ -24,15 +24,28 @@ const Convenience = Self.imports.convenience;
 
 let wallpaperController;
 let extensionMeta;
+let panelEntry;
 
 function init(metaData) {
 	extensionMeta = metaData;
 	wallpaperController = new WallpaperController.WallpaperController(metaData);
 }
 
-let panelEntry;
+function enable() {
+	// enable Extension
+	// UI
+	panelEntry = new RandomWallpaperEntry(0, "Random wallpaper");
 
-let RandomWallpaperEntry = new Lang.Class({
+	// add to panel
+	Main.panel.addToStatusArea("random-wallpaper-menu", panelEntry);
+}
+
+function disable() {
+	// disable Extension
+	panelEntry.destroy();
+}
+
+var RandomWallpaperEntry = new Lang.Class({
 	Extends: PanelMenu.Button,
 	Name: "RandomWallpaperEntry",
 	logger: null,
@@ -80,7 +93,6 @@ let RandomWallpaperEntry = new Lang.Class({
 		/*
 			add eventlistener
 		*/
-
 		wallpaperController.registerStartLoadingHook(this.statusIcon.startLoading.bind(this.statusIcon));
 		wallpaperController.registerStopLoadingHook(this.statusIcon.stopLoading.bind(this.statusIcon));
 		wallpaperController.registerStopLoadingHook(this.setHistoryList.bind(this));
@@ -168,8 +180,6 @@ let RandomWallpaperEntry = new Lang.Class({
 			this.historySection.addMenuItem(tmp);
 		}
 
-		let _this = this;
-
 		function onLeave(actor) {
 			wallpaperController.resetWallpaper();
 		}
@@ -196,18 +206,3 @@ let RandomWallpaperEntry = new Lang.Class({
 	},
 
 });
-
-function enable() {
-	// Extension enabled
-
-	// UI
-	panelEntry = new RandomWallpaperEntry(0, "Random wallpaper");
-
-	// add to panel
-	Main.panel.addToStatusArea("random-wallpaper-menu", panelEntry);
-}
-
-function disable() {
-	// Extension disabled
-	panelEntry.destroy();
-}
diff --git a/randomwallpaper@iflow.space/history.js b/randomwallpaper@iflow.space/history.js
index ab7a151..155f76b 100644
--- a/randomwallpaper@iflow.space/history.js
+++ b/randomwallpaper@iflow.space/history.js
@@ -9,7 +9,7 @@ const Prefs = Self.imports.settings;
 
 const LoggerModule = Self.imports.logger;
 
-let HistoryEntry = new Lang.Class({
+var HistoryEntry = new Lang.Class({
 	Name: "HistoryEntry",
 	timestamp: null,
 	id: null,
@@ -29,7 +29,7 @@ let HistoryEntry = new Lang.Class({
 	},
 });
 
-let HistoryController = new Lang.Class({
+var HistoryController = new Lang.Class({
 	Name: "HistoryController",
 	_settings: null,
 	_wallpaperlocation: null,
diff --git a/randomwallpaper@iflow.space/jsonpath/jsonpath.js b/randomwallpaper@iflow.space/jsonpath/jsonpath.js
index 81c75a4..2f1d0bd 100644
--- a/randomwallpaper@iflow.space/jsonpath/jsonpath.js
+++ b/randomwallpaper@iflow.space/jsonpath/jsonpath.js
@@ -1,4 +1,4 @@
-let JSONPathParser = function () {
+var JSONPathParser = function () {
 
 	/**
 	 * Access a simple json path expression of an object.
diff --git a/randomwallpaper@iflow.space/logger.js b/randomwallpaper@iflow.space/logger.js
index 9481ac9..3187c3c 100644
--- a/randomwallpaper@iflow.space/logger.js
+++ b/randomwallpaper@iflow.space/logger.js
@@ -1,6 +1,6 @@
 const Lang = imports.lang;
 
-let Logger = new Lang.Class({
+var Logger = new Lang.Class({
 	Name: "Logger",
 	_prefix: null,
 	_callingClass: null,
diff --git a/randomwallpaper@iflow.space/prefs.js b/randomwallpaper@iflow.space/prefs.js
index b466ffc..91d7e80 100644
--- a/randomwallpaper@iflow.space/prefs.js
+++ b/randomwallpaper@iflow.space/prefs.js
@@ -32,7 +32,7 @@ function buildPrefsWidget() {
 }
 
 /* UI Setup */
-const RandomWallpaperSettings = new Lang.Class({
+var RandomWallpaperSettings = new Lang.Class({
 	Name: 'RandomWallpaper.Settings',
 	logger: null,
 
diff --git a/randomwallpaper@iflow.space/settings.js b/randomwallpaper@iflow.space/settings.js
index 84fe953..9db69eb 100644
--- a/randomwallpaper@iflow.space/settings.js
+++ b/randomwallpaper@iflow.space/settings.js
@@ -5,7 +5,7 @@ const Gio = imports.gi.Gio;
 const Self = imports.misc.extensionUtils.getCurrentExtension();
 const Convenience = Self.imports.convenience;
 
-let Settings = new Lang.Class({
+var Settings = new Lang.Class({
 	Name: "Settings",
 	_settings: null,
 
diff --git a/randomwallpaper@iflow.space/sourceAdapter.js b/randomwallpaper@iflow.space/sourceAdapter.js
index ad80e7a..3d364e4 100644
--- a/randomwallpaper@iflow.space/sourceAdapter.js
+++ b/randomwallpaper@iflow.space/sourceAdapter.js
@@ -16,7 +16,7 @@ const HistoryModule = Self.imports.history;
 const LoggerModule = Self.imports.logger;
 const JSONPath = Self.imports.jsonpath.jsonpath;
 
-let BaseAdapter = new Lang.Class({
+var BaseAdapter = new Lang.Class({
 	Name: "BaseAdapter",
 	logger: null,
 
@@ -45,7 +45,7 @@ let BaseAdapter = new Lang.Class({
 
 });
 
-let DesktopperAdapter = new Lang.Class({
+var DesktopperAdapter = new Lang.Class({
 	Name: "DesktopperAdapter",
 	Extends: BaseAdapter,
 
@@ -85,7 +85,7 @@ let DesktopperAdapter = new Lang.Class({
 	}
 });
 
-let UnsplashAdapter = new Lang.Class({
+var UnsplashAdapter = new Lang.Class({
 	Name: "UnsplashAdapter",
 	Extends: BaseAdapter,
 
@@ -177,7 +177,7 @@ let UnsplashAdapter = new Lang.Class({
 	}
 });
 
-let WallheavenAdapter = new Lang.Class({
+var WallheavenAdapter = new Lang.Class({
 	Name: "WallheavenAdapter",
 	Extends: BaseAdapter,
 	_settings: null,
@@ -280,7 +280,7 @@ let WallheavenAdapter = new Lang.Class({
 	}
 });
 
-let GenericJsonAdapter = new Lang.Class({
+var GenericJsonAdapter = new Lang.Class({
 	Name: "GenericJsonAdapter",
 	Extends: BaseAdapter,
 
diff --git a/randomwallpaper@iflow.space/timer.js b/randomwallpaper@iflow.space/timer.js
index c822261..a2d243e 100644
--- a/randomwallpaper@iflow.space/timer.js
+++ b/randomwallpaper@iflow.space/timer.js
@@ -7,7 +7,7 @@ const Prefs = Self.imports.settings;
 let _afTimerInstance = null;
 
 // Singleton implementation of _AFTimer
-let AFTimer = function() {
+var AFTimer = function() {
     if (!_afTimerInstance) {
         _afTimerInstance = new _AFTimer();
     }
@@ -20,7 +20,7 @@ let AFTimer = function() {
  * TODO: find way to store elapsed time on shutdown/logout/gnome-shell-restart/etc.
  * @type {Lang}
  */
-let _AFTimer = new Lang.Class({
+var _AFTimer = new Lang.Class({
     Name: 'AFTimer',
 
     _timeout: null,
diff --git a/randomwallpaper@iflow.space/wallpaperController.js b/randomwallpaper@iflow.space/wallpaperController.js
index 408a72c..0298d18 100644
--- a/randomwallpaper@iflow.space/wallpaperController.js
+++ b/randomwallpaper@iflow.space/wallpaperController.js
@@ -18,7 +18,7 @@ const HistoryModule = Self.imports.history;
 
 const LoggerModule = Self.imports.logger;
 
-let WallpaperController = new Lang.Class({
+var WallpaperController = new Lang.Class({
 	Name: "WallpaperController",
 	extensionMeta: null,
 	logger: null,