diff --git a/src/core/commoniface.py b/src/core/commoniface.py
index 02b288fd..2f0e139f 100644
--- a/src/core/commoniface.py
+++ b/src/core/commoniface.py
@@ -27,8 +27,11 @@
 def genrevalock(appname, value):
     '''Return a base64-encoded lock compatible with the Reva implementation of the CS3 Lock API'''
     return urlsafe_b64encode(json.dumps(
-        {'h': appname if appname else 'wopi', 't': int(time.time()), 'md': value}
-        ).encode()).decode()
+        {'type': 'LOCK_TYPE_SHARED',
+         'h': appname if appname else 'wopi',
+         'md': value,
+         'mtime': int(time.time()),
+        }).encode()).decode()
 
 def retrieverevalock(rawlock):
     '''Restores the JSON payload from a base64-encoded Reva lock'''