Is it possible to recover old deleted email? Like a month ago? Thanks!
Define “deleted”. If in the trash folder still, then yes … but if the trash has been emptied, then no.
If you keep incremental backups that far back you could first backup your MIAB (important!!), restore the old backup, sync a temporary account in an e-mail program with it, retrieve the e-mail (or just find it in Roundcube), then restore the new MIAB backup and carry on.
That is if you don’t mind disruptions to the e-mail service and take off the server offline immediately after you sync the temporary e-mail program or find the e-mail (because otherwise the “old” MIAB instance will receive e-mails and those e-mails will be lost when you overwrite it again with the new backup).
Depending on how you retrieve your backups via FTP your old backups might still be there. All backups have different filenames so they don’t overwrite each other. If your FTP program isn’t set to delete files that don’t exist on the server (for example not using mirror -e in lftp), then your local folder will contain all the old backups unless you’ve manually cleaned them up.
This all of course hinges on the fact that the e-mail must’ve been present in one of the backups. If you received the e-mail, moved it to trash and deleted from there in one day, before the next backup was triggered, then you’re SOL