diff --git a/packetserver/runners/http_user_manager.py b/packetserver/runners/http_user_manager.py
index b073ba7..680a034 100644
--- a/packetserver/runners/http_user_manager.py
+++ b/packetserver/runners/http_user_manager.py
@@ -28,21 +28,18 @@ HTTP_USERS_KEY = "httpUsers"
 
 
 def open_database(db_arg: str) -> ZODB.DB:
-    """
-    Open a ZODB database from either a local FileStorage path or ZEO address.
-    """
-    if ":" in db_arg and db_arg.count(":") == 1 and "." in db_arg.split(":")[0]:
-        import ZEO
-        host, port_str = db_arg.split(":")
-        try:
-            port = int(port_str)
-        except ValueError:
-            raise ValueError(f"Invalid port in ZEO address: {db_arg}")
-        return ZEO.DB((host,port))
-    else:
-        # Local FileStorage path
-        storage = ZODB.FileStorage.FileStorage(db_arg)
-        return ZODB.DB(storage)
+    if ":" in db_arg:
+        parts = db_arg.split(":")
+        if len(parts) == 2 and parts[1].isdigit():
+            import ZEO
+            host = parts[0]
+            port = int(parts[1])
+            storage = ZEO.client((host, port))  # modern ZEO
+            return ZODB.DB(storage)
+
+    # Local
+    storage = ZODB.FileStorage.FileStorage(db_arg)
+    return ZODB.DB(storage)
 
 
 def get_or_create_http_users(root):
@@ -133,8 +130,7 @@ def main():
 
             main_users = root.setdefault('users', PersistentMapping())
             if callsign not in main_users:
-                new_user = User(callsign)
-                new_user.write_new(root)
+                User.write_new(main_users, args.callsign)  # correct: pass mapping + callsign
                 print(f"  → Also created regular BBS user {callsign} (with UUID)")
             else:
                 print(f"  → Regular BBS user {callsign} already exists")