migrate to virtual mailboxes before upgrading to 2.4

Hello,

I was thinking about, maybe, migrating my postfix/dovecot server to virtual mailboxes, before upgrading Debian to Trixie.

So, atm, I have system users with ~/Maildir but it's not so convenient anymore. I am looking for some documentation/guide on how to migrate everything to virtual mailboxes. Of course I searched by myself, but didn't find many results.

Thanks

-- roughnecks