How mutt check to download emails from an imap server without downloading them more than once?

[Cameron Simpson]

On 19Mar2023 09:52, Peng Yu <pengyu.ut at gmail.com> wrote:
>I use the following python code to download UNDELETED messages. But it
>will fetch all messages without considering whether an message has
>been downloaded previously. How does mutt solve this problem to only
>download the emails that have not been downloaded before.

Mutt knows the message-ids of messages in the current mailbox. Skip 
those message-ids.

Cheers,
Cameron Simpson <cs at cskk.id.au>