Comment # 11 on bug 1207963 from Yasuhiko Kamata

Thanks again for testing.

As a side note, the "TLS" setting in kmail means to use STARTTLS command.
This is specified at RFC-2595 (POP3) and RFC-3207 (SMTP).

https://www.rfc-editor.org/rfc/rfc2595.html
https://www.rfc-editor.org/rfc/rfc3207.html

You can use STARTTLS them with:
 openssl s_client -starttls pop3 -connect pop.actrix.co.nz:110
 openssl s_client -starttls smtp -connect smtp.actrix.co.nz:587

In a (normal) SSL connection, encryption is performed from the beginning of the
connection.
But in a STARTTLS ("TLS") connection, encryption is performed only AFTER the
"STARTTLS" command.