Deprecate MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 3cd1d62..8bab913 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -721,6 +721,13 @@
* HMAC implementation which also truncates the key
* (Mbed TLS versions from 1.3 to 2.6.0) */
mac_key_len = transform->maclen;
+
+#if defined(MBEDTLS_DEPRECATED_WARNING)
+#warning MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT is deprecated and should only be \
+ enabled temporarily when (1) the use of truncated HMAC is essential in order \
+ to save bandwidth, and (2) the peer is an Mbed TLS stack that doesn not use the \
+ fixed implementation yet (version number <= 2.6.0).
+#endif
#endif
}
#endif /* MBEDTLS_SSL_TRUNCATED_HMAC */