diff --git a/voc/schedule.py b/voc/schedule.py
index 244cad4..8cd94e0 100644
--- a/voc/schedule.py
+++ b/voc/schedule.py
@@ -709,7 +709,7 @@ def _to_etree(d, node, parent=""):
                             # not in schedule.json: license information for an event
                             v = {
                                 "license": recording_license,
-                                "optout": "true" if v is True else "false",
+                                "optout": v,
                             }
                         # new style schedule.json (version 2022-12)
                         elif k == "optout":