diff --git a/composer.json b/composer.json
index e7a3b27..4ab94a1 100644
--- a/composer.json
+++ b/composer.json
@@ -10,7 +10,6 @@
         "psr/simple-cache": "^3.0.0"
     },
     "require-dev": {
-        "silverstripe/framework": "^5",
         "phpunit/phpunit": "^9.5",
         "mikey179/vfsstream": "^1.6",
         "squizlabs/php_codesniffer": "^3.7"
@@ -21,4 +20,4 @@
             "SilverStripe\\Config\\Tests\\": "tests/"
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/Collections/MemoryConfigCollection.php b/src/Collections/MemoryConfigCollection.php
index 5963a5c..b87af73 100644
--- a/src/Collections/MemoryConfigCollection.php
+++ b/src/Collections/MemoryConfigCollection.php
@@ -117,7 +117,11 @@ public function checkForDeprecatedConfig($class, $name): void
         $deprecated = $this->getClassConfig('__deprecated', true);
         $data = $deprecated['config'][strtolower($class)][$name] ?? [];
         if (!empty($data)) {
-            Deprecation::notice($data['version'], $data['message'], Deprecation::SCOPE_CONFIG);
+            if (class_exists(Deprecation::class)) {
+                Deprecation::notice($data['version'], $data['message'], Deprecation::SCOPE_CONFIG);
+            } else {
+                user_error($data['message'], E_USER_DEPRECATED);
+            }
         }
     }