diff --git a/composer.json b/composer.json
index 9923320..3888376 100644
--- a/composer.json
+++ b/composer.json
@@ -30,7 +30,9 @@
     }
   },
   "require": {
-    "oxid-esales/oxideshop-ce": "6.0 - 6.3"
+    "php": ">=5.6",
+    "oxid-esales/oxideshop-ce": "6.0 - 6.3",
+    "spipu/html2pdf": "^5.2"
   },
   "autoload": {
     "psr-4": {