Without support for STARTTLS it's not possible to test for protocol such as SMTP, POP3, IMAP, FTP, etc. which might be able to do SSL/TLS after an initial cleartext negociation, depending on the server.
For example, openssl s_client support:
-starttls prot - use the STARTTLS command before starting TLS
for those protocols that support it, where
'prot' defines which one to assume. Currently,
only "smtp", "pop3", "imap", "ftp" and "xmpp"
are supported.
Without support for STARTTLS it's not possible to test for protocol such as SMTP, POP3, IMAP, FTP, etc. which might be able to do SSL/TLS after an initial cleartext negociation, depending on the server.
For example,
openssl s_clientsupport: