diff --git a/extension.js b/extension.js
index c920725..689e926 100644
--- a/extension.js
+++ b/extension.js
@@ -15,9 +15,6 @@
 
 const {Clutter, Gio, Meta} = imports.gi;
 
-const Config               = imports.misc.config;
-const [GS_MAJOR, GS_MINOR] = Config.PACKAGE_VERSION.split('.');
-
 const Workspace                  = imports.ui.workspace.Workspace;
 const WindowManager              = imports.ui.windowManager.WindowManager;
 const WINDOW_REPOSITIONING_DELAY = imports.ui.workspace.WINDOW_REPOSITIONING_DELAY;
@@ -89,7 +86,7 @@ class Extension {
     // overview window layout. Therefore we call this method in addition.
     // https://gitlab.gnome.org/GNOME/gnome-shell/-/blob/gnome-3-36/js/ui/workspace.js#L1877
     // https://gitlab.gnome.org/GNOME/gnome-shell/-/blob/main/js/ui/workspace.js#L1415
-    if (GS_MAJOR == 3 && GS_MINOR == 36) {
+    if (utils.shellVersionIs(3, 36)) {
       Workspace.prototype._addWindowClone = function(...params) {
         const [clone, overlay] = extensionThis._origAddWindowClone.apply(this, params);
         clone.connect('destroy', () => this._doRemoveWindow(clone.metaWindow));
diff --git a/src/common/utils.js b/src/common/utils.js
index 1dead0a..61827a8 100644
--- a/src/common/utils.js
+++ b/src/common/utils.js
@@ -15,6 +15,9 @@
 
 const {Gtk} = imports.gi;
 
+const Config               = imports.misc.config;
+const [GS_MAJOR, GS_MINOR] = Config.PACKAGE_VERSION.split('.');
+
 const ExtensionUtils = imports.misc.extensionUtils;
 const Me             = imports.misc.extensionUtils.getCurrentExtension();
 
@@ -42,3 +45,19 @@ function debug(message) {
 function isGTK4() {
   return Gtk.get_major_version() == 4;
 }
+
+function shellVersionIs(major, minor) {
+  return GS_MAJOR == major && GS_MINOR == minor;
+}
+
+function shellVersionIsAtLeast(major, minor) {
+  if (GS_MAJOR > major) {
+    return true;
+  }
+
+  if (GS_MAJOR == major) {
+    return GS_MINOR >= minor;
+  }
+
+  return false;
+}
\ No newline at end of file
diff --git a/src/prefs/FirePage.js b/src/prefs/FirePage.js
index a4afbe6..66a700b 100644
--- a/src/prefs/FirePage.js
+++ b/src/prefs/FirePage.js
@@ -62,10 +62,6 @@ var FirePage = class FirePage extends PrefsPage {
 
   // ---------------------------------------------------------------------- public methods
 
-  getMinVersion() {
-    return [3, 36];
-  }
-
   getEnabledKey() {
     return 'fire-close-effect';
   }
diff --git a/src/prefs/MatrixPage.js b/src/prefs/MatrixPage.js
index a8404a9..e6dbf47 100644
--- a/src/prefs/MatrixPage.js
+++ b/src/prefs/MatrixPage.js
@@ -15,6 +15,7 @@
 
 const ExtensionUtils = imports.misc.extensionUtils;
 const Me             = imports.misc.extensionUtils.getCurrentExtension();
+const utils          = Me.imports.src.common.utils;
 const PrefsPage      = Me.imports.src.prefs.PrefsPage.PrefsPage;
 
 //////////////////////////////////////////////////////////////////////////////////////////
@@ -27,6 +28,10 @@ var MatrixPage = class MatrixPage extends PrefsPage {
   constructor(settings, builder) {
     super(settings, builder);
 
+    if (!utils.shellVersionIsAtLeast(40, 0)) {
+      return;
+    }
+
     this._builder.add_from_resource('/ui/gtk4/matrixPage.ui');
 
     // Bind all properties.
@@ -42,10 +47,6 @@ var MatrixPage = class MatrixPage extends PrefsPage {
 
   // ---------------------------------------------------------------------- public methods
 
-  getMinVersion() {
-    return [40, 0];
-  }
-
   getEnabledKey() {
     return 'matrix-close-effect';
   }
diff --git a/src/prefs/TRexPage.js b/src/prefs/TRexPage.js
index 7248b4e..633cfff 100644
--- a/src/prefs/TRexPage.js
+++ b/src/prefs/TRexPage.js
@@ -15,6 +15,7 @@
 
 const ExtensionUtils = imports.misc.extensionUtils;
 const Me             = imports.misc.extensionUtils.getCurrentExtension();
+const utils          = Me.imports.src.common.utils;
 const PrefsPage      = Me.imports.src.prefs.PrefsPage.PrefsPage;
 
 //////////////////////////////////////////////////////////////////////////////////////////
@@ -27,6 +28,10 @@ var TRexPage = class TRexPage extends PrefsPage {
   constructor(settings, builder) {
     super(settings, builder);
 
+    if (!utils.shellVersionIsAtLeast(40, 0)) {
+      return;
+    }
+
     this._builder.add_from_resource('/ui/gtk4/trexPage.ui');
 
     // Bind all properties.
@@ -42,10 +47,6 @@ var TRexPage = class TRexPage extends PrefsPage {
 
   // ---------------------------------------------------------------------- public methods
 
-  getMinVersion() {
-    return [40, 0];
-  }
-
   getEnabledKey() {
     return 'trex-close-effect';
   }
diff --git a/src/prefs/TVEffectPage.js b/src/prefs/TVEffectPage.js
index 17b371a..284bd1b 100644
--- a/src/prefs/TVEffectPage.js
+++ b/src/prefs/TVEffectPage.js
@@ -40,10 +40,6 @@ var TVEffectPage = class TVEffectPage extends PrefsPage {
 
   // ---------------------------------------------------------------------- public methods
 
-  getMinVersion() {
-    return [3, 36];
-  }
-
   getEnabledKey() {
     return 'tv-close-effect';
   }