Backed-up emails are pushed to the IMAP server. If there are clashes, folders are renamed.
If, when the backup is launched, the IMAP server contains a folder with the same name, but different history to the local backup, the local emails cannot simply be added to the existing folder.
In this case, a numeric suffix is added to the local folder, before it is restored.
In this way, old and new emails are kept separate.
No.
Emails are identified by folder and a specific email id. Any email that is already on the server is skipped.
- Run setup and add the new server, (but don't run any backups),
- Rename of the existing backup directory to match the new email address,
- Run the restore.