diff --git a/src/Extensions/ContentReviewDefaultSettings.php b/src/Extensions/ContentReviewDefaultSettings.php
index d14d587..1c8e155 100644
--- a/src/Extensions/ContentReviewDefaultSettings.php
+++ b/src/Extensions/ContentReviewDefaultSettings.php
@@ -110,7 +110,7 @@ class ContentReviewDefaultSettings extends DataExtension
     /**
      * @param FieldList $fields
      */
-    public function updateCMSFields(FieldList $fields)
+    protected function updateCMSFields(FieldList $fields)
     {
         $helpText = LiteralField::create(
             'ContentReviewHelp',
diff --git a/src/Extensions/ContentReviewLeftAndMainExtension.php b/src/Extensions/ContentReviewLeftAndMainExtension.php
index e882b16..9984eb8 100644
--- a/src/Extensions/ContentReviewLeftAndMainExtension.php
+++ b/src/Extensions/ContentReviewLeftAndMainExtension.php
@@ -15,7 +15,7 @@ class ContentReviewLeftAndMainExtension extends LeftAndMainExtension
      *
      * @param array &$clientConfig
      */
-    public function updateClientConfig(&$clientConfig)
+    protected function updateClientConfig(&$clientConfig)
     {
         $clientConfig['form']['ReviewContentForm'] = [
             'schemaUrl' => $this->owner->Link('schema/ReviewContentForm')
diff --git a/src/Extensions/ContentReviewOwner.php b/src/Extensions/ContentReviewOwner.php
index d72f1b3..260fd49 100644
--- a/src/Extensions/ContentReviewOwner.php
+++ b/src/Extensions/ContentReviewOwner.php
@@ -23,7 +23,7 @@ class ContentReviewOwner extends DataExtension
         "SiteTreeContentReview" => SiteTree::class,
     ];
 
-    public function updateCMSFields(FieldList $fields)
+    protected function updateCMSFields(FieldList $fields)
     {
         // Remove automatically scaffolded GridField in Member CMS fields
         $fields->removeByName('SiteTreeContentReview');
diff --git a/src/Extensions/SiteTreeContentReview.php b/src/Extensions/SiteTreeContentReview.php
index 2e00dd4..10f072e 100644
--- a/src/Extensions/SiteTreeContentReview.php
+++ b/src/Extensions/SiteTreeContentReview.php
@@ -161,7 +161,7 @@ class SiteTreeContentReview extends DataExtension implements PermissionProvider
     /**
      * @param FieldList $actions
      */
-    public function updateCMSActions(FieldList $actions)
+    protected function updateCMSActions(FieldList $actions)
     {
         if (!$this->canBeReviewedBy(Security::getCurrentUser())) {
             return;
@@ -326,7 +326,7 @@ class SiteTreeContentReview extends DataExtension implements PermissionProvider
     /**
      * @param FieldList $fields
      */
-    public function updateSettingsFields(FieldList $fields)
+    protected function updateSettingsFields(FieldList $fields)
     {
         if ($this->owner->hasMethod('displayContentReview') && !$this->owner->displayContentReview()) {
             return;
@@ -564,7 +564,7 @@ class SiteTreeContentReview extends DataExtension implements PermissionProvider
     /**
      * Set the review data from the review period, if set.
      */
-    public function onBeforeWrite()
+    protected function onBeforeWrite()
     {
         // Only update if DB fields have been changed
         $changedFields = $this->owner->getChangedFields(true, 2);