Automatically check for new mail

If you want Evolution to check automatically for new messages, enable the option Check for new messages every … minutes in the Receiving Options page of the mail account settings (accessible via Edit ▸ Preferences ▸ Mail Accounts ▸ Edit ▸ Receiving Options) and select the frequency in minutes.

Evolution supports IMAP IDLE on the currently selected folder and partially supports the IMAP NOTIFY extension.