diff --git a/doc/obex-api.txt b/doc/obex-api.txt
index 31afc74..f80ef39 100644
--- a/doc/obex-api.txt
+++ b/doc/obex-api.txt
@@ -491,12 +491,10 @@ Properties	string Folder [readonly]
 
 			Current folder.
 
-		string DatabaseIdentifier [readonly]
+		string DatabaseIdentifier [readonly, optional]
 
 			128 bits persistent identifier.
 
-			Value '0' shall be considered as not supported.
-
 
 Synchronization hierarchy
 =========================