Newer version of courier-imap will no longer be able to write the IPs into the relay table. This is because all authentication has now been moved out of courier (and sqwebmail) and into the courier-authlib package. As has always been the case, authdaemon doesn't support POP before SMTP. That's why I chose never to use authdaemon.
Now that courier no longer supports POP before SMTP via the authvchkpw module, it's just one more good reason not to use courier-imap for POP3 services. Use qmails pop3d instead. That way POP users still get roaming access. IMAP users are users newer email clients that support SMTP AUTH and should be directed to use that instead.
I have overcome this via the relay-ctrl package. My roaming users don't roam very often, but -do- (and are required to) use DDNS. Via their DDNS record, I can easily access their machine if need be...but I digress.
I have written a -simple- perl cron that reverse queries their name/ip mapping, and updates the relay-ctrl directory of the allowed ip's that can relay. This way, I'm still using courier. (not that qmail-pop is bad, I've used it too...just have courier in this case)
Just my approach.