diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 1874d4f..80cb4bf 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -723,8 +723,18 @@
      * ( also known as ossification ). Otherwise, it MUST be set as a zero-length
      * vector ( i.e., a zero-valued single byte length field ).
      */
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+    MBEDTLS_SSL_CHK_BUF_PTR( p, end, ssl->session_negotiate->id_len + 1 );
+    *p++ = (unsigned char)ssl->session_negotiate->id_len;
+    memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->id_len );
+    p += ssl->session_negotiate->id_len;
+
+    MBEDTLS_SSL_DEBUG_BUF( 3, "session id", ssl->session_negotiate->id,
+                              ssl->session_negotiate->id_len );
+#else
     MBEDTLS_SSL_CHK_BUF_PTR( p, end, 1 );
     *p++ = 0; /* session id length set to zero */
+#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
 
     /* Write cipher_suites */
     ret = ssl_tls13_write_client_hello_cipher_suites( ssl, p, end, &output_len );
@@ -843,6 +853,24 @@
         return( ret );
     }
 
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+    /*
+     * Create a session identifier for the purpose of middlebox compatibility
+     * only if one has not been created already.
+     */
+    if( ssl->session_negotiate->id_len == 0 )
+    {
+        /* Creating a session id with 32 byte length */
+        if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng,
+                                      ssl->session_negotiate->id, 32 ) ) != 0 )
+        {
+            MBEDTLS_SSL_DEBUG_RET( 1, "creating session id failed", ret );
+            return( ret );
+        }
+        ssl->session_negotiate->id_len = 32;
+    }
+#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
+
     return( 0 );
 }
 
@@ -1611,8 +1639,14 @@
     if( ret != 0 )
         return( ret );
 
-    mbedtls_ssl_set_outbound_transform( ssl, ssl->handshake->transform_handshake );
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+    mbedtls_ssl_handshake_set_state(
+        ssl,
+        MBEDTLS_SSL_CLIENT_CCS_AFTER_SERVER_FINISHED );
+#else
     mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_FINISHED );
+#endif
+
     return( 0 );
 }
 
@@ -1623,6 +1657,8 @@
 {
     int ret;
 
+    mbedtls_ssl_set_outbound_transform( ssl, ssl->handshake->transform_handshake );
+
     ret = mbedtls_ssl_tls13_write_finished_message( ssl );
     if( ret != 0 )
         return( ret );
@@ -1713,6 +1749,15 @@
             ret = ssl_tls13_handshake_wrapup( ssl );
             break;
 
+        /*
+         * Injection of dummy-CCS's for middlebox compatibility
+         */
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+        case MBEDTLS_SSL_CLIENT_CCS_AFTER_SERVER_FINISHED:
+            ret = mbedtls_ssl_tls13_write_change_cipher_spec( ssl );
+            break;
+#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
+
         default:
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
             return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );