diff --git a/src/Extensions/ElementalAreaUsedOnTableExtension.php b/src/Extensions/ElementalAreaUsedOnTableExtension.php
index 0fd8ff33..3d828407 100644
--- a/src/Extensions/ElementalAreaUsedOnTableExtension.php
+++ b/src/Extensions/ElementalAreaUsedOnTableExtension.php
@@ -20,7 +20,7 @@ class ElementalAreaUsedOnTableExtension extends DataExtension
      *
      * @var array $excludedClasses
      */
-    public function updateUsageExcludedClasses(array &$excludedClasses)
+    protected function updateUsageExcludedClasses(array &$excludedClasses)
     {
         $excludedClasses[] = ElementalArea::class;
     }
@@ -31,7 +31,7 @@ public function updateUsageExcludedClasses(array &$excludedClasses)
      * @param bool $excludeDataObject
      * @param DataObject $dataObject|null
      */
-    public function updateUsageDataObject(?DataObject &$dataObject)
+    protected function updateUsageDataObject(?DataObject &$dataObject)
     {
         if (!($dataObject instanceof BaseElement)) {
             return;
@@ -51,7 +51,7 @@ public function updateUsageDataObject(?DataObject &$dataObject)
      * @param array $ancestorDataObjects
      * @param DataObject $dataObject
      */
-    public function updateUsageAncestorDataObjects(array &$ancestorDataObjects, DataObject $dataObject)
+    protected function updateUsageAncestorDataObjects(array &$ancestorDataObjects, DataObject $dataObject)
     {
         if (!($dataObject instanceof BaseElement)) {
             return;
diff --git a/src/Extensions/ElementalAreasExtension.php b/src/Extensions/ElementalAreasExtension.php
index 565e2618..09562b5f 100644
--- a/src/Extensions/ElementalAreasExtension.php
+++ b/src/Extensions/ElementalAreasExtension.php
@@ -175,7 +175,7 @@ public function getElementalRelations()
      *
      * @param FieldList
      */
-    public function updateCMSFields(FieldList $fields)
+    protected function updateCMSFields(FieldList $fields)
     {
         if (!$this->supportsElemental()) {
             return;
diff --git a/src/Extensions/ElementalCMSMainExtension.php b/src/Extensions/ElementalCMSMainExtension.php
index 530b8135..c4bdc1f6 100644
--- a/src/Extensions/ElementalCMSMainExtension.php
+++ b/src/Extensions/ElementalCMSMainExtension.php
@@ -18,7 +18,7 @@ class ElementalCMSMainExtension extends Extension
      *
      * @param Form $form
      */
-    public function updateSearchForm(Form $form)
+    protected function updateSearchForm(Form $form)
     {
         /** @var DropdownField $filterField */
         $filterField = $form->Fields()->fieldByName('Search__FilterClass');
diff --git a/src/Extensions/ElementalPageExtension.php b/src/Extensions/ElementalPageExtension.php
index e775f508..c63fa4dd 100644
--- a/src/Extensions/ElementalPageExtension.php
+++ b/src/Extensions/ElementalPageExtension.php
@@ -103,7 +103,7 @@ public function getContentFromElementsForCmsSearch(): string
     /**
      * @see SiteTree::getAnchorsOnPage()
      */
-    public function updateAnchorsOnPage(array &$anchors): void
+    protected function updateAnchorsOnPage(array &$anchors): void
     {
         if (!($this->owner instanceof SiteTree)) {
             return;
diff --git a/src/Extensions/GridFieldAddNewMultiClassHandlerExtension.php b/src/Extensions/GridFieldAddNewMultiClassHandlerExtension.php
index 1da3c610..975fb75b 100644
--- a/src/Extensions/GridFieldAddNewMultiClassHandlerExtension.php
+++ b/src/Extensions/GridFieldAddNewMultiClassHandlerExtension.php
@@ -15,7 +15,7 @@ class GridFieldAddNewMultiClassHandlerExtension extends Extension
     /**
      * @param Form $form
      */
-    public function updateItemEditForm(Form $form)
+    protected function updateItemEditForm(Form $form)
     {
         // NOTE: this extension is applied to new item edit form only
 
diff --git a/src/Extensions/GridFieldDetailFormItemRequestExtension.php b/src/Extensions/GridFieldDetailFormItemRequestExtension.php
index 2e562f63..b2e8264b 100644
--- a/src/Extensions/GridFieldDetailFormItemRequestExtension.php
+++ b/src/Extensions/GridFieldDetailFormItemRequestExtension.php
@@ -12,7 +12,7 @@
  */
 class GridFieldDetailFormItemRequestExtension extends Extension
 {
-    public function updateBreadcrumbs($crumbs)
+    protected function updateBreadcrumbs($crumbs)
     {
         $record = $this->owner->getRecord();
 
diff --git a/src/TopPage/DataExtension.php b/src/TopPage/DataExtension.php
index a2d0d602..b70d216c 100644
--- a/src/TopPage/DataExtension.php
+++ b/src/TopPage/DataExtension.php
@@ -64,7 +64,7 @@ public function onAfterWrite(): void
     /**
      * Extension point in @see DataObject::duplicate()
      */
-    public function onBeforeDuplicate(): void
+    protected function onBeforeDuplicate(): void
     {
         $this->clearTopPage();
     }
@@ -72,7 +72,7 @@ public function onBeforeDuplicate(): void
     /**
      * Extension point in @see DataObject::duplicate()
      */
-    public function onAfterDuplicate(): void
+    protected function onAfterDuplicate(): void
     {
         $this->updateTopPage();
     }
@@ -198,7 +198,7 @@ public function withFixedTopPage(int $topPageID, callable $callback)
         }
     }
 
-    public function updateCMSFields(FieldList $fields)
+    protected function updateCMSFields(FieldList $fields)
     {
         $fields->removeByName('TopPageID');
     }
diff --git a/src/TopPage/FluentExtension.php b/src/TopPage/FluentExtension.php
index d81e86ae..fa802875 100644
--- a/src/TopPage/FluentExtension.php
+++ b/src/TopPage/FluentExtension.php
@@ -29,7 +29,7 @@ class FluentExtension extends DataExtension
         'TopPageLocale' => 'Varchar',
     ];
 
-    public function updateCMSFields(FieldList $fields)
+    protected function updateCMSFields(FieldList $fields)
     {
         $fields->removeByName('TopPageID');
         $fields->removeByName('TopPageLocale');
diff --git a/src/TopPage/SiteTreeExtension.php b/src/TopPage/SiteTreeExtension.php
index 320576d6..58789bf0 100644
--- a/src/TopPage/SiteTreeExtension.php
+++ b/src/TopPage/SiteTreeExtension.php
@@ -48,7 +48,7 @@ public function onAfterWrite(): void
      *
      * @param SiteTree $original
      */
-    public function onBeforeDuplicate(SiteTree $original): void
+    protected function onBeforeDuplicate(SiteTree $original): void
     {
         $this->initDuplication($original);
     }
@@ -60,7 +60,7 @@ public function onBeforeDuplicate(SiteTree $original): void
      * @param bool $doWrite
      * @throws ValidationException
      */
-    public function onAfterDuplicate(SiteTree $original, $doWrite): void
+    protected function onAfterDuplicate(SiteTree $original, $doWrite): void
     {
         $this->processDuplication($original, (bool) $doWrite);
     }
diff --git a/tests/Extensions/ElementalCMSMainExtensionTest.php b/tests/Extensions/ElementalCMSMainExtensionTest.php
index 464007d3..f5a022c2 100644
--- a/tests/Extensions/ElementalCMSMainExtensionTest.php
+++ b/tests/Extensions/ElementalCMSMainExtensionTest.php
@@ -7,6 +7,7 @@
 use SilverStripe\Forms\DropdownField;
 use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\Form;
+use \ReflectionMethod;
 
 class ElementalCMSMainExtensionTest extends SapphireTest
 {
@@ -19,7 +20,10 @@ public function testRemovesDefaultEmptyStringFromClassFilter()
         $fields = new FieldList($field);
         $form = new Form(null, null, $fields, new FieldList());
 
-        $extension->updateSearchForm($form);
+        // Call extension method ElementalCMSMainExtension::updateSearchForm($form) which is protected
+        $method = new ReflectionMethod(ElementalCMSMainExtension::class, 'updateSearchForm');
+        $method->setAccessible(true);
+        $method->invoke($extension, $form);
 
         $this->assertEmpty($field->getEmptyString(), 'Empty string should be empty');
         $this->assertFalse($field->getHasEmptyDefault(), 'Empty string should not have an empty default');