diff --git a/src/libcharon/plugins/systime_fix/systime_fix_validator.h b/src/libcharon/plugins/systime_fix/systime_fix_validator.h
index 591377c15..477c55fe5 100644
--- a/src/libcharon/plugins/systime_fix/systime_fix_validator.h
+++ b/src/libcharon/plugins/systime_fix/systime_fix_validator.h
@@ -44,7 +44,9 @@ struct systime_fix_validator_t {
 
 /**
  * Create a systime_fix_validator instance.
+ *
+ * @param threshold		timestamp where we start to consider system time valid
  */
-systime_fix_validator_t *systime_fix_validator_create();
+systime_fix_validator_t *systime_fix_validator_create(time_t threshold);
 
 #endif /** SYSTIME_FIX_VALIDATOR_H_ @}*/