diff --git a/extension.json b/extension.json
index 993663a0..910f9a89 100644
--- a/extension.json
+++ b/extension.json
@@ -6,7 +6,7 @@
 	"license-name": "GPL-2.0-or-later",
 	"type": "parserhook",
 	"requires": {
-		"MediaWiki": ">= 1.38.0"
+		"MediaWiki": ">= 1.40.0"
 	},
 	"ConfigRegistry": {
 		"categorytree": "GlobalVarConfig::newInstance"
@@ -92,7 +92,10 @@
 	"HookHandlers": {
 		"default": {
 			"class": "MediaWiki\\Extension\\CategoryTree\\Hooks",
-			"services": [ "CategoryTree.CategoryCache", "MainConfig" ]
+			"services": [
+				"CategoryTree.CategoryCache",
+				"MainConfig"
+			]
 		},
 		"config": {
 			"class": "MediaWiki\\Extension\\CategoryTree\\ConfigHookHandler"
diff --git a/includes/CategoryCache.php b/includes/CategoryCache.php
index e9e93dfd..42f5552c 100644
--- a/includes/CategoryCache.php
+++ b/includes/CategoryCache.php
@@ -20,7 +20,7 @@
 
 namespace MediaWiki\Extension\CategoryTree;
 
-use Category;
+use MediaWiki\Category\Category;
 use MediaWiki\Linker\LinkTarget;
 use Wikimedia\Rdbms\ILoadBalancer;
 use Wikimedia\Rdbms\IResultWrapper;
diff --git a/includes/CategoryTree.php b/includes/CategoryTree.php
index 01f3ca9a..578f9e00 100644
--- a/includes/CategoryTree.php
+++ b/includes/CategoryTree.php
@@ -24,12 +24,12 @@
 
 namespace MediaWiki\Extension\CategoryTree;
 
-use Category;
 use Exception;
 use ExtensionRegistry;
 use FormatJson;
 use Html;
 use IContextSource;
+use MediaWiki\Category\Category;
 use MediaWiki\Linker\LinkRenderer;
 use MediaWiki\MediaWikiServices;
 use OutputPage;
diff --git a/tests/phpunit/CategoryCacheTest.php b/tests/phpunit/CategoryCacheTest.php
index f271f07b..b2bd6440 100644
--- a/tests/phpunit/CategoryCacheTest.php
+++ b/tests/phpunit/CategoryCacheTest.php
@@ -20,7 +20,7 @@
 
 namespace MediaWiki\Extension\CategoryTree\Tests;
 
-use Category;
+use MediaWiki\Category\Category;
 use MediaWiki\Extension\CategoryTree\CategoryCache;
 use MediaWikiIntegrationTestCase;
 use TitleValue;