diff --git a/phpunit-api.xml b/phpunit-api.xml
index b38a3c0f..38a53ca4 100644
--- a/phpunit-api.xml
+++ b/phpunit-api.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <phpunit
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.4/phpunit.xsd"
+    xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
     bootstrap="./config/test/bootstrap_api_tests.php"
     colors="true"
 >
diff --git a/phpunit-db.xml b/phpunit-db.xml
index 030f777b..b2dd8008 100644
--- a/phpunit-db.xml
+++ b/phpunit-db.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <phpunit
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.4/phpunit.xsd"
+    xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
     bootstrap="./config/test/bootstrap_db_tests.php"
     colors="true"
 >
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 9c8e02df..29c60b6b 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <phpunit
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.4/phpunit.xsd"
+    xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
     bootstrap="./vendor/autoload.php"
     colors="true"
 >