After a migration, the emails are seen with the backup copy date, not the actual date.
How can I change the display date of the email?
not sure, but I think - its not rounsdcube deals. I think its backup/restore results.
When I do migrate - I use utils who directly copy messages from old imap to new imap and do date correction on fly.
How did you take the backup?
While taking backup, you need to preserve the time stamp.
and while restoring, you need to do the same.
For example.
Mail dir = /home/xyz/mail
for backup: tar -czpf xyz-mail.tgz /home/xyz/mail
for restore: tar -xzpf xyz-mail.tgz
Here, the option -p is used to preserve the timestamp and ownership.