diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index b8980f2..e8a2f36 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -1198,6 +1198,9 @@
  *          bandwidth, and (2) the peer is an Mbed TLS stack that doesn't use
  *          the fixed implementation yet (pre-2.1.10).
  *
+ * \deprecated This option is deprecated and will likely be removed in a
+ *             future version of Mbed TLS.
+ *
  * Uncomment to fallback to old, non-compliant truncated HMAC implementation.
  *
  * Requires: MBEDTLS_SSL_TRUNCATED_HMAC