diff --git a/js/responsive_menu.superfish.js b/js/responsive_menu.superfish.js
index a5b99bb..b32ebcb 100644
--- a/js/responsive_menu.superfish.js
+++ b/js/responsive_menu.superfish.js
@@ -1,4 +1,4 @@
-(function ($) {
+(function ($, once) {
 
   'use strict';
 
@@ -13,7 +13,7 @@
   Drupal.behaviors.responsive_menu_optional = {
     attach: function (context, settings) {
 
-      $(context).find('body').once('responsive-menu-optional').each(function () {
+      $(once('responsive-menu-optional', 'body', context)).each(function () {  
 
         // Apply the superfish library to the menu.
         if ($.fn.superfish && drupalSettings.responsive_menu.superfish.active) {
@@ -33,4 +33,4 @@
     }
   };
 
-})(jQuery);
+})(jQuery, once);
diff --git a/responsive_menu.info.yml b/responsive_menu.info.yml
index 427b0a1..8e0b387 100644
--- a/responsive_menu.info.yml
+++ b/responsive_menu.info.yml
@@ -1,10 +1,9 @@
 name: "Responsive menu"
 description: "Provides a javascript based off-canvas responsive menu with depth. At wider browser widths it provides a horizontal menu capable of drop downs and flyouts."
-core: 8.x
 package: Other
 configure: responsive_menu.settings
 dependencies:
   - drupal:breakpoint
   - drupal:system (>=8.8)
 type: module
-core_version_requirement: ^8 || ^9
+core_version_requirement: ^9.3 || ^10
diff --git a/responsive_menu.libraries.yml b/responsive_menu.libraries.yml
index e166f0e..703eb4f 100644
--- a/responsive_menu.libraries.yml
+++ b/responsive_menu.libraries.yml
@@ -29,7 +29,7 @@ responsive_menu.superfish:
   dependencies:
     - responsive_menu/responsive_menu.config
     - core/jquery
-    - core/jquery.once
+    - core/once
 
 responsive_menu.superfish_hoverintent:
   version: VERSION
diff --git a/responsive_menu.module b/responsive_menu.module
index 7e48d5f..65a30a6 100644
--- a/responsive_menu.module
+++ b/responsive_menu.module
@@ -21,9 +21,9 @@ define('RESPONSIVE_MENU_BREAKPOINT_FILENAME', '/responsive_menu_breakpoint.css')
 function responsive_menu_help($route_name, RouteMatchInterface $route_match) {
   switch ($route_name) {
     case 'responsive_menu.settings':
-      $readme = Link::fromTextAndUrl('README.md', Url::fromUri('base:' . drupal_get_path('module', 'responsive_menu') . '/README.md'))->toRenderable();
+      $readme = Link::fromTextAndUrl('README.md', Url::fromUri('base:' . \Drupal::service('extension.list.module')->getPath('responsive_menu') . '/README.md'))->toRenderable();
       return '<p>' . t('3rd party libraries are required to enable some of the features. See the @readme file for more information about where to download and place them.', [
-        '@readme' => render($readme),
+        '@readme' => \Drupal::service('renderer')->render($readme),
       ]) . '</p><p>' . t("At a minimum you need to place the 'Responsive menu mobile icon' block in a region. If you want to display a horizontal menu at a specified breakpoint then you also need to place the 'Horizontal menu' block, although this is optional.") . '</p>';
   }
 }
diff --git a/src/Form/SettingsForm.php b/src/Form/SettingsForm.php
index 1686337..35a86d0 100644
--- a/src/Form/SettingsForm.php
+++ b/src/Form/SettingsForm.php
@@ -313,7 +313,7 @@ class SettingsForm extends ConfigFormBase {
     if ($values['use_breakpoint'] && empty($values['horizontal_breakpoint'])) {
       $breakpoint_message = Link::fromTextAndUrl('breakpoint file', Url::fromUri('https://www.drupal.org/node/1803874'))->toRenderable();
       $form_state->setErrorByName('horizontal_breakpoint', $this->t("You have chosen to use a breakpoint but you have not selected one. This may happen if your @breakpoint is not properly set up.", [
-        '@breakpoint' => render($breakpoint_message),
+        '@breakpoint' => \Drupal::service('renderer')->render($breakpoint_message),
       ]));
     }
   }
diff --git a/tests/modules/responsive_menu_test/responsive_menu_test.info.yml b/tests/modules/responsive_menu_test/responsive_menu_test.info.yml
index 4bd9435..c878806 100644
--- a/tests/modules/responsive_menu_test/responsive_menu_test.info.yml
+++ b/tests/modules/responsive_menu_test/responsive_menu_test.info.yml
@@ -2,6 +2,7 @@ name: 'Responsive Menu Test'
 type: module
 description: 'Support module for Responsive Menu tests.'
 package: Testing
+core_version_requirement: ^9.3 || ^10
 dependencies:
   - drupal:node
   - drupal:filter
diff --git a/tests/themes/responsive_menu_theme_test_nobp/responsive_menu_theme_test_nobp.info.yml b/tests/themes/responsive_menu_theme_test_nobp/responsive_menu_theme_test_nobp.info.yml
index 9df4b0f..ce6ed81 100644
--- a/tests/themes/responsive_menu_theme_test_nobp/responsive_menu_theme_test_nobp.info.yml
+++ b/tests/themes/responsive_menu_theme_test_nobp/responsive_menu_theme_test_nobp.info.yml
@@ -1,5 +1,5 @@
 name: 'Responsive menu test theme (no breakpoints)'
 type: theme
 description: 'Test theme for responsive_menu module.'
-core: 8.x
+core_version_requirement: ^9.3 || ^10
 base theme: stable