[tuwtuwtuwtuw]

Http3, IMAP, Caldav and MAPI?

Cordinating a client across two ports sounds trivial compared to for example properly implementing client and server versions of IMAP search commands when no client or server follows the specification.

[pixl97]

Until you realize that the two ports commonly involve dealing with middleware that cant handle it properly.

[tuwtuwtuwtuw]

You will have similar issues with other protocols as well. I have seen physical bandwidth limiters, windows drivers, corrupt winsock LSPs etc mess with IMAP traffic. I have seen middleware replacing SMTP commands sent from a client to server for no good reason, such as replacing "EHLO hostname" with "EHLO **".