diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index fedb2be..6cf47fe 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -1455,6 +1455,13 @@
             return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
         }
 
+        /*
+         * Version 1.2 of the protocol has been negotiated, set the
+         * ssl->keep_current_message flag for the ServerHello to be kept and
+         * parsed as a TLS 1.2 ServerHello. We also change ssl->tls_version to
+         * MBEDTLS_SSL_VERSION_TLS1_2 thus from now on mbedtls_ssl_handshake_step()
+         * will dispatch to the TLS 1.2 state machine.
+         */
         ssl->keep_current_message = 1;
         ssl->tls_version = MBEDTLS_SSL_VERSION_TLS1_2;
         MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum(ssl,