The original email file name pattern looks like this:
1447902202.31829.old-domain.com,S=15459960_2,S
If we are going to migrate to another email server, should we rename the host name part of the file name so that it becomes:
1447902202.31829.new-domain.com,S=15459960_2,S
Or it simply does not matter? Some users might have been using different email clients to access their emails via IMAP. Do typical email clients use the email file name as the id to identify an email or they will actually inspect inside the email file and locate the message id from the header?