901725 - [RFE] Implement "remove old emails from server" for IMAP also

Status: UNCONFIRMED

(MailNews Core :: Networking: IMAP, enhancement)

Description

[Samuel LB]

Use case:

- IMAP accout with a mail quota (say 100 MB)
- User has two computers/devices that runs Thunderbird (and has e.g. 500 GB of disk)
- You want to keep your mail "forever" on both devices.

In this situation you run out of mail quota after some time, but still have lots of disk space. It would be useful to have an option to have e-mail deleted from the server after some time (such that both devices can download new mails) - e.g. after 30 days. Currently this is only possible with POP accounts, and you have to create separate local folders if you want to keep your IMAP mail.

Turning on this option would change four things in Thunderbird:

1) the option "Keep messages for this account on this computer" under "Synchronization & Storage" in Account Settings is activated and greyed out.
2) if an e-mail is found to be deleted from the server, this no longer causes it to be deleted locally.
3) e-mails on the server get deleted after a specified number of days after they have been downloaded.
4) local e-mail is not copied to the server if it's older than the specified time.