diff --git a/crypto/err/ssl.errordata b/crypto/err/ssl.errordata
index 46ff44f..9bc295d 100644
--- a/crypto/err/ssl.errordata
+++ b/crypto/err/ssl.errordata
@@ -166,6 +166,7 @@
 SSL,216,SSL_SESSION_ID_CONTEXT_TOO_LONG
 SSL,290,SSL_SESSION_ID_TOO_LONG
 SSL,276,TICKET_ENCRYPTION_FAILED
+SSL,297,TLS13_DOWNGRADE
 SSL,1049,TLSV1_ALERT_ACCESS_DENIED
 SSL,1050,TLSV1_ALERT_DECODE_ERROR
 SSL,1021,TLSV1_ALERT_DECRYPTION_FAILED