I have a piece of software with a mailclient that has problems when it POP's large amounts of mail. Unfortunately the system can't be updated or fixed.So I'm trying to figure out if I can limit the number of mails that can be seen via Dovecot. ... So it would be a question of always presenting a maximum of 300 mails via the POP3.Is it doable?
You're probably solving the wrong problem -- the mail client really ought to be able to process 300+ messages. It may be a better use of time to fix that than to torture dovecot to give you what you want.
You can try using a plugin to define a virtual INBOX
https://wiki.dovecot.org/Plugins/Virtualwith search/selection criteria to limit the number of messages.
You can also try some LDA script (e.g. procmail) hackery to create INBOX volumes of 300 messages, then do some shuffling around when the INBOX gets emptied.
Joseph Tam jtam.home@gmail.com