Add description of CID feature to ChangeLog
diff --git a/ChangeLog b/ChangeLog
index 978b8b5..b1117c6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,17 @@
= mbed TLS 2.x.x branch released xxxx-xx-xx
+Features
+ * Add support for draft-05 of the Connection ID extension, as specified
+ in https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05.
+ The Connection ID extension allows to keep DTLS connections beyond the
+ lifetime of the underlying transport by adding a connection identifier
+ to the DTLS record header. This identifier can be used to associated an
+ incoming record with the correct connection data even after the peer has
+ changed its IP or port. The feature is enabled at compile-time by setting
+ MBEDTLS_SSL_DTLS_CONNECTION_ID (disabled by default), and at run-time
+ through the new APIs mbedtls_ssl_conf_cid() and mbedtls_ssl_set_cid().
+
Security
* Make mbedtls_ecdh_get_params return an error if the second key
belongs to a different group from the first. Before, if an application