diff --git a/docs/RELEASE-NOTES.md b/docs/RELEASE-NOTES.md
index e4398bbe..7b8e2b0a 100644
--- a/docs/RELEASE-NOTES.md
+++ b/docs/RELEASE-NOTES.md
@@ -63,7 +63,7 @@ Tidy YAML files
 
     # Run single tests
     cd /var/www/sites/d8_webform
-    php core/scripts/run-tests.sh --verbose --class "Drupal\webform\Tests\WebformSubmissionStorageTest"
+    php core/scripts/run-tests.sh --url http://localhost/wf --verbose --class "Drupal\Tests\webform\Functional\WebformListBuilderTest"
 
 [PHPUnit](https://www.drupal.org/node/2116263)
      
@@ -83,6 +83,7 @@ References
 
     # Execute individual PHPUnit tests.
     export SIMPLETEST_DB=mysql://drupal_d8_webform:drupal.@dm1n@localhost/drupal_d8_webform;
+    export SIMPLETEST_BASE_URL='http://localhost/wf';
 
     # Functional test.    
     php ../vendor/phpunit/phpunit/phpunit --printer="\Drupal\Tests\Listeners\HtmlOutputPrinter" ../modules/sandbox/webform/tests/src/Functional/WebformExampleFunctionalTest.php
diff --git a/includes/webform.theme.inc b/includes/webform.theme.inc
index e55fc7a0..1ba24d29 100644
--- a/includes/webform.theme.inc
+++ b/includes/webform.theme.inc
@@ -305,6 +305,13 @@ function webform_preprocess_fieldset(&$variables) {
   if (isset($variables['legend']['title'])) {
     _webform_preprocess_help_title($variables['legend']['title'], $element);
   }
+
+  // Add .js-webform-form-composite class to be used #states API.
+  // @see js/webform.states.js
+  if (isset($element['#type']) && in_array($element['#type'], ['checkboxes', 'radios'])) {
+    $variables['attributes']['class'][] = 'js-webform-type-' . $element['#type'];
+    $variables['attributes']['class'][] = 'webform-type-' . $element['#type'];
+  }
 }
 
 /**
diff --git a/js/webform.element.radios.js b/js/webform.element.radios.js
deleted file mode 100644
index e6fc4964..00000000
--- a/js/webform.element.radios.js
+++ /dev/null
@@ -1,60 +0,0 @@
-/**
- * @file
- * JavaScript behaviors for radio buttons.
- *
- * Fix #states and #required for radios buttons.
- *
- * @see Issue #2856795: If radio buttons are required but not filled form is nevertheless submitted.
- * @see Issue #2856315: Conditional Logic - Requiring Radios in a Fieldset.
- * @see Issue #2731991: Setting required on radios marks all options required.
- * @see css/webform.form.css
- * @see /core/misc/states.js
- */
-
-(function ($, Drupal) {
-
-  'use strict';
-
-  /**
-   * Attach handler to add .js-webform-radios-fieldset to radios wrapper fieldset.
-   *
-   * @type {Drupal~behavior}
-   */
-  Drupal.behaviors.webformRadios = {
-    attach: function (context) {
-      $('.js-webform-radios', context).closest('fieldset.form-composite').addClass('js-webform-radios-fieldset');
-    }
-  };
-
-  // Make absolutely sure the below event handlers are triggered after
-  // the /core/misc/states.js event handlers by attaching them after DOM load.
-  $(function () {
-    Drupal.behaviors.webformRadios.attach($(document));
-
-    function setRequired($target, required) {
-      if (!$target.hasClass('js-webform-radios-fieldset') && !$target.hasClass('js-webform-radios-other')) {
-        return;
-      }
-
-      if (required) {
-        $target.find('input[type="radio"]').attr({'required': 'required', 'aria-required': 'aria-required'});
-        $target.find('legend span').addClass('js-form-required form-required');
-      }
-      else {
-        $target.find('input[type="radio"]').removeAttr('required aria-required');
-        $target.find('legend span').removeClass('js-form-required form-required');
-      }
-    }
-
-    $('.js-webform-radios-fieldset[required="required"], .js-form-type-webform-radios-other[required="required"]').each(function() {
-      setRequired($(this), true);
-    });
-
-    $(document).on('state:required', function (e) {
-      if (e.trigger) {
-        setRequired($(e.target), e.value);
-      }
-    });
-  });
-
-})(jQuery, Drupal);
diff --git a/js/webform.states.js b/js/webform.states.js
index eaa339a3..4d90596f 100644
--- a/js/webform.states.js
+++ b/js/webform.states.js
@@ -50,16 +50,56 @@
 
   var $document = $(document);
 
-  // Issue #2860529: Conditional required File upload field don't work.
   $document.on('state:required', function (e) {
     if (e.trigger) {
+      var $target = $(e.target);
+      // Fix #required file upload.
+      // @see Issue #2860529: Conditional required File upload field don't work.
       if (e.value) {
-        $(e.target).find('input[type="file"]').attr({'required': 'required', 'aria-required': 'aria-required'});
+        $target.find('input[type="file"]').attr({'required': 'required', 'aria-required': 'aria-required'});
       }
       else {
-        $(e.target).find('input[type="file"]').removeAttr('required aria-required');
+        $target.find('input[type="file"]').removeAttr('required aria-required');
+      }
+
+      // Fix #required for radios buttons.
+      // @see Issue #2856795: If radio buttons are required but not filled form is nevertheless submitted.
+      if ($target.is('.js-webform-type-radios, .js-form-type-webform-radios-other')) {
+        if (e.value) {
+          $target.find('input[type="radio"]').attr({'required': 'required', 'aria-required': 'aria-required'});
+        }
+        else {
+          $target.find('input[type="radio"]').removeAttr('required aria-required');
+        }
+      }
+
+      // Fix #required for checkboxes buttons.
+      // @see Issue #2938414: Checkboxes don't support #states required
+      if ($target.is('.js-webform-type-checkboxes, .js-form-type-webform-checkboxes-other')) {
+        if (e.value) {
+          $target.find('input[type="checkbox"]').attr({'required': 'required', 'aria-required': 'aria-required'});
+          $target.find('input[type="checkbox"]').bind('click', checkboxRequiredhandler);
+        }
+        else {
+          $target.find('input[type="checkbox"]').removeAttr('required aria-required');
+          $target.find('input[type="checkbox"]').unbind('click', checkboxRequiredhandler);
+        }
+      }
+
+      // Fix required label for checkboxes and radios.
+      // @see Issue #2938414: Checkboxes don't support #states required
+      // @see Issue #2731991: Setting required on radios marks all options required.
+      // @see Issue #2856315: Conditional Logic - Requiring Radios in a Fieldset.
+      if ($target.is('.js-webform-type-radios, .js-webform-type-checkboxes')) {
+        if (e.value) {
+          $target.find('legend span').addClass('js-form-required form-required');
+        }
+        else {
+          $target.find('legend span').removeClass('js-form-required form-required');
+        }
       }
     }
+
   });
 
   $document.on('state:readonly', function (e) {
@@ -102,6 +142,21 @@
     }
   });
 
+  /**
+   * Trigger custom HTML5 multiple checkboxes validation.
+   *
+   * @see https://stackoverflow.com/a/37825072/145846
+   */
+  function checkboxRequiredhandler() {
+    var $checkboxes = $(this).closest('.js-webform-type-checkboxes, .js-form-type-webform-checkboxes-other').find('input[type="checkbox"]');
+    if ($checkboxes.is(':checked')) {
+      $checkboxes.removeAttr('required aria-required');
+    }
+    else {
+      $checkboxes.attr({'required': 'required', 'aria-required': 'aria-required'});
+    }
+  }
+
   /**
    * Trigger an input's event handlers.
    *
diff --git a/src/Plugin/WebformElement/Radios.php b/src/Plugin/WebformElement/Radios.php
index a44a5766..c4f52bb8 100644
--- a/src/Plugin/WebformElement/Radios.php
+++ b/src/Plugin/WebformElement/Radios.php
@@ -30,16 +30,4 @@ class Radios extends OptionsBase {
     ] + parent::getDefaultProperties();
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function prepare(array &$element, WebformSubmissionInterface $webform_submission = NULL) {
-    parent::prepare($element, $webform_submission);
-
-    // Issue #2856795: If radio buttons are required but not filled form is
-    // nevertheless submitted.
-    // Issue #2856315: Conditional Logic - Requiring Radios in a Fieldset.
-    $element['#attached']['library'][] = 'webform/webform.element.radios';
-  }
-
 }
diff --git a/tests/modules/webform_test/config/install/webform.webform.test_element_checkboxes.yml b/tests/modules/webform_test/config/install/webform.webform.test_element_checkboxes.yml
index 6f36efc5..4e6baa00 100644
--- a/tests/modules/webform_test/config/install/webform.webform.test_element_checkboxes.yml
+++ b/tests/modules/webform_test/config/install/webform.webform.test_element_checkboxes.yml
@@ -49,6 +49,30 @@ elements: |
       '#title_display': inline
       '#options': yes_no
       '#options_display': side_by_side
+  checkboxes_required_conditional_example:
+    '#type': details
+    '#title': 'Checkboxes required conditional'
+    '#open': true
+    checkboxes_required_conditional_trigger:
+      '#type': checkbox
+      '#title': 'Require the below checkboxes'
+      '#default_value': true
+    checkboxes_required_conditions:
+      '#type': checkboxes
+      '#title': checkboxes_required
+      '#options': yes_no
+      '#states':
+        required:
+          ':input[name="checkboxes_required_conditional_trigger"]':
+            checked: true
+    checkboxes_other_required_conditions:
+      '#type': webform_checkboxes_other
+      '#title': checkboxes_other_required
+      '#options': yes_no
+      '#states':
+        required:
+          ':input[name="checkboxes_required_conditional_trigger"]':
+            checked: true
 css: ''
 javascript: ''
 settings:
diff --git a/tests/modules/webform_test/config/install/webform.webform.test_element_radios.yml b/tests/modules/webform_test/config/install/webform.webform.test_element_radios.yml
index 89b68898..8eb3074a 100644
--- a/tests/modules/webform_test/config/install/webform.webform.test_element_radios.yml
+++ b/tests/modules/webform_test/config/install/webform.webform.test_element_radios.yml
@@ -28,7 +28,7 @@ elements: |
     '#open': true
     radios_required_conditional_trigger:
       '#type': checkbox
-      '#title': 'Required the below radio button'
+      '#title': 'Require the below radio button'
       '#default_value': true
     radios_required_conditions:
       '#type': radios
@@ -38,6 +38,14 @@ elements: |
         required:
           ':input[name="radios_required_conditional_trigger"]':
             checked: true
+    radios_other_required_conditions:
+      '#type': webform_radios_other
+      '#title': radios_other_required
+      '#options': yes_no
+      '#states':
+        required:
+          ':input[name="radios_required_conditional_trigger"]':
+            checked: true
   buttons_required_conditional_example:
     '#type': details
     '#title': 'Buttons required conditional'
diff --git a/webform.libraries.yml b/webform.libraries.yml
index 67da03e3..b7f53163 100644
--- a/webform.libraries.yml
+++ b/webform.libraries.yml
@@ -653,15 +653,6 @@ webform.element.other:
     - core/jquery
     - core/jquery.once
 
-webform.element.radios:
-  version: VERSION
-  js:
-    js/webform.element.radios.js: {}
-  dependencies:
-    - core/drupal
-    - core/jquery
-    - core/jquery.once
-
 webform.element.range:
   version: VERSION
   css: