diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index d8844fc..883b988 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -2150,6 +2150,9 @@
                                            unsigned char *buf,
                                            const unsigned char *end,
                                            size_t *out_len);
+
+int mbedtls_ssl_tls13_check_early_data_len(mbedtls_ssl_context *ssl,
+                                           size_t early_data_len);
 #endif /* MBEDTLS_SSL_EARLY_DATA */
 
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 */