I have just migrated my emails to a new mail server. The old and the new server had the exact same setup using MailDir with fetchmail, procmail and dovecot. The configurations of those three applications are mostly the default configurations.
I just copied my old emails to the new MailDir folder "cur". (according to the answers in Dovecot Migration and old mails)
Now when I connect to the IMAP server with Thunderbird, it downloads all the mails including the ones which I just migrated and pasted into the new folders.
However, and that is the problem, when I try to download the emails from the new server using my other email client Geary, or my iPhone, only those emails are downloaded which have been newly fetched from my email provider. Emails which I copied into the existing server folders (migrated) do not show up in these clients.
Am I missing something in the configuration of dovecot or is this a problem of my mail clients? How could the new and the old emails be different and distinguished by dovecot?