diff --git a/src/matrix-api-types.c b/src/matrix-api-types.c
index cfc936f..520ab7f 100644
--- a/src/matrix-api-types.c
+++ b/src/matrix-api-types.c
@@ -50,6 +50,8 @@
  *                                  for the homeserver
  * @MATRIX_API_ERROR_NOT_JSON: illegal request, the content is not
  *                             valid JSON
+ * @MATRIX_API_ERROR_UNRECOGNIZED: the homeserver didn't understand
+ *                                 the request
  * @MATRIX_API_ERROR_UNSPECIFIED: no error code was sent by the
  *                                homeserver
  * @MATRIX_API_ERROR_UNKNOWN_ERROR: an error unknown to this library
diff --git a/src/matrix-api-types.h b/src/matrix-api-types.h
index 40de754..84d114d 100644
--- a/src/matrix-api-types.h
+++ b/src/matrix-api-types.h
@@ -39,6 +39,7 @@ typedef enum {
     MATRIX_API_ERROR_UNKNOWN,
     MATRIX_API_ERROR_UNKNOWN_TOKEN,
     MATRIX_API_ERROR_NOT_JSON,
+    MATRIX_API_ERROR_UNRECOGNIZED,
 
     /* Allow for a lot of Matrix.org defined codes
        Do not define error codes after this! */