diff --git a/drmproperty.h b/drmproperty.h
index eb5fcb5..1ebd665 100644
--- a/drmproperty.h
+++ b/drmproperty.h
@@ -27,6 +27,7 @@
 enum DrmPropertyType {
   DRM_PROPERTY_TYPE_INT,
   DRM_PROPERTY_TYPE_ENUM,
+  DRM_PROPERTY_TYPE_INVALID,
 };
 
 class DrmProperty {