diff --git a/doc/api/tls.md b/doc/api/tls.md
index 3b0420eddc5251..e66e7ffe719506 100644
--- a/doc/api/tls.md
+++ b/doc/api/tls.md
@@ -669,19 +669,19 @@ to implement the `tls-unique` channel binding from [RFC 5929][].
 added: v5.7.0
 -->
 
-* Returns: {string}
+* Returns: {string|null}
 
 Returns a string containing the negotiated SSL/TLS protocol version of the
 current connection. The value `'unknown'` will be returned for connected
 sockets that have not completed the handshaking process. The value `null` will
 be returned for server sockets or disconnected client sockets.
 
-Example responses include:
+Protocol versions are:
 
-* `TLSv1`
-* `TLSv1.1`
-* `TLSv1.2`
-* `unknown`
+* `'TLSv1'`
+* `'TLSv1.1'`
+* `'TLSv1.2'`
+* `'SSLv3'`
 
 See <https://www.openssl.org/docs/man1.1.0/ssl/SSL_get_version.html> for more
 information.