How do I download only new messages in imap?

How do I download only new messages in imap? How do I download only new messages in imap? I have over 15 000 emails, do not want everyone on my computer is too slow.

Hello Neto,
unfortunately there is no way to do such thing - synchronization with the server through IMAP protocol means mirroring every item that is on the server.
What eM Client does for IMAP protocol though is synchronizing only the message headers by default and downloads the whole message only after you want to access it (after you open it).
To download all of your messages you’d need to check the ‘Download messages for offline use’ option in the Tools>Accounts section under the IMAP tab.

Regards,
Olivia

can you subscribe to certain folders? If not I’ll be d#l the headers for 25K archived emails Im not interested having on all my client PCs.

No, you cannot subscribe to folders in eM Client.  I think other clients do allow this.