diff --git a/composer.json b/composer.json
index 86a9ed01f5..9687bf3b85 100644
--- a/composer.json
+++ b/composer.json
@@ -15,6 +15,7 @@
         "ext-xml": "*",
         "ext-curl": "*",
         "ext-exif": "*",
+        "ext-pdo": "*",
         "psr/log": "1.1.*",
         "psr/http-message": "^1.0",
         "slim/slim": "^4.7",