diff --git a/include/polarssl/config.h b/include/polarssl/config.h
index 220f74d..76972dd 100644
--- a/include/polarssl/config.h
+++ b/include/polarssl/config.h
@@ -107,6 +107,9 @@
  *
  * Note: on Windows/MingW, XP or higher is required.
  *
+ * \warning As of 1.3.11, *not* using this flag when POLARSSL_NET_C is
+ * defined, is deprecated. The alternative legacy code will be removed in 2.0.
+ *
  * Comment if your system does not support the IPv6 socket interface
  */
 #define POLARSSL_HAVE_IPV6
@@ -1757,6 +1760,9 @@
  *
  * Enable the TCP/IP networking routines.
  *
+ * \warning As of 1.3.11, it is deprecated to enable this module without
+ * POLARSSL_HAVE_IPV6. The alternative legacy code will be removed in 2.0.
+ *
  * Module:  library/net.c
  *
  * This module provides TCP/IP networking routines.