user-defined special-use folders

I plan to define SPECIAL-USE mailboxes and think about defining per user special-use folders for those who don't use the default folder names. Is this possible in dovecot?

What I try: $ doveadm exec imap

• PREAUTH [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS BINARY MOVE SEARCH=FUZZY METADATA SPECIAL-USE] Logged in as fschmidt a1 SETMETADATA "sent-mail" (/private/specialuse "\\Sent") a1 NO [CANNOT] The /private/specialuse attribute cannot be changed (0.008

• 0.000 + 0.008 secs).

using dovecot 2.2.29.1, following the example in RFC 6154, sect. 5.4

(How is MAIL_ATTRIBUTE_INTERNAL_RANK_AUTHORITY defined or set?)

Fabian.