diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 597da25..e34e3af 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -4449,6 +4449,24 @@
  *                 with \c mbedtls_ssl_read()), not handshake messages.
  *                 With DTLS, this affects both ApplicationData and handshake.
  *
+ * \note           Defragmentation of incoming handshake messages in TLS
+ *                 (excluding DTLS) is supported with some limitations:
+ *                 - On an Mbed TLS server that only accepts TLS 1.2,
+ *                   the initial ClientHello message must not be fragmented.
+ *                   A TLS 1.2 ClientHello may be fragmented if the server
+ *                   also accepts TLS 1.3 connections (meaning
+ *                   that #MBEDTLS_SSL_PROTO_TLS1_3 enabled, and the
+ *                   accepted versions have not been restricted with
+ *                   mbedtls_ssl_conf_max_tls_version() or the like).
+ *                 - A ClientHello message that initiates a renegotiation
+ *                   must not be fragmented.
+ *                 - The first fragment of a handshake message must be
+ *                   at least 4 bytes long.
+ *                 - Non-handshake records must not be interleaved between
+ *                   the fragments of a handshake message. (This is permitted
+ *                   in TLS 1.2 but not in TLS 1.3, but Mbed TLS rejects it
+ *                   even in TLS 1.2.)
+ *
  * \note           This sets the maximum length for a record's payload,
  *                 excluding record overhead that will be added to it, see
  *                 \c mbedtls_ssl_get_record_expansion().