diff --git a/lib/wp/spa-json.c b/lib/wp/spa-json.c
index 5f1878dd..ca03099a 100644
--- a/lib/wp/spa-json.c
+++ b/lib/wp/spa-json.c
@@ -265,6 +265,7 @@ wp_spa_json_get_size (const WpSpaJson *self)
  * \ingroup wpspajson
  * \param self a spa json object
  * \returns (transfer full): the json string with length matching the size
+ * \since 0.4.11
  */
 gchar *
 wp_spa_json_to_string (const WpSpaJson *self)