[Dovecot] is it posible to autocreate imap folders with non ascii chars?

Hello.

I'm migrating from cyrus to dovecot and now after i converted mailboxes to Maildir. Some users already has imap folders with cyrillic chars. How could i autocreate folders with cyrillic chars? When i type something like: ... autocreate = utf8_chars autosubscribe = utf8_chars ...

In logs i see that dovecot complains: Apr 05 16:21:43 imap(pavelkor): Debug: autocreate: Failed to create mailbox utf8_chars: Invalid mailbox name

It is even possible to achieve?