1 files changed, 5 insertions, 2 deletions
diff --git a/src/backend/taler-merchant-httpd_private-patch-otp-devices-ID.c b/src/backend/taler-merchant-httpd_private-patch-otp-devices-ID.c
index cb784b8d..596b8b09 100644
--- a/src/backend/taler-merchant-httpd_private-patch-otp-devices-ID.c
+++ b/src/backend/taler-merchant-httpd_private-patch-otp-devices-ID.c
@@ -46,8 +46,11 @@ TMH_private_patch_otp_devices_ID (const struct TMH_RequestHandler *rh,
       GNUNET_JSON_spec_uint64 ("otp_ctr",
                                &tp.otp_ctr),
       NULL),
-    TALER_JSON_spec_otp_key ("otp_key",
-                             (const char **) &tp.otp_key),
+    GNUNET_JSON_spec_mark_optional(
+
+      TALER_JSON_spec_otp_key ("otp_key",
+                               (const char **) &tp.otp_key),
+      NULL),
     GNUNET_JSON_spec_end ()
   };