sort the articles on imap server by date physically

[Uwe Brauer]

Hello

Due to some changes and collapses of the mail sytem, some of my mail
on the imap server, in some folders, is not in chronological order.
With gnus I can sort it by date, however this sorting is not
permanent. VM on the other hand offers a possibility to sort messages
either virtually or physically. Does gnus offer such a
functionality. I searched the documentation but without success.

Thanks 

Uwe Brauer