diff --git a/src/Proxy/AbstractProxy.php b/src/Proxy/AbstractProxy.php
index da9a4daa..9577a483 100644
--- a/src/Proxy/AbstractProxy.php
+++ b/src/Proxy/AbstractProxy.php
@@ -106,7 +106,7 @@ protected function getParameterCode(ReflectionParameter $parameter)
         if (PHP_VERSION_ID >= 70000) {
             $reflectionType = $parameter->getType();
             if ($reflectionType) {
-                $nullablePrefix = $reflectionType->allowsNull() ? '?' : '';
+                $nullablePrefix = (PHP_VERSION_ID >= 70100 && $reflectionType->allowsNull()) ? '?' : '';
                 $nsPrefix       = $reflectionType->isBuiltin() ? '' : '\\';
                 $type           = $nullablePrefix . $nsPrefix . (string) $reflectionType;
             }