I have a mail client which I use to download messages from my Gmail account. However, for one reason or another the download of some messages failed, and I have two gaps in particular - each of about a week or two, which I would like to download. In the settings I can select "download all messages" or "download messages that arrive from now on". How can I tell it to download all messages as of a certain date, or all messages inside certain date ranges?
Edit: my client is a POP email client.