[Dovecot] zlib_save per-user or per-mailbox?

We'd like to be able to activate zlib_save per-user or per-mailbox, but it seems to be global, all or nothing. Search of this list revealed a comment from Timo in 2012:

http://www.dovecot.org/list/dovecot/2012-March/064909.html

where he was thinking that compression per-namespace would be a worthy feature. Was that done?

I'm in the process of replacing a 2.0 system with 2.2 EE. The old system had zlib_save activated, but seems to deliver to maildirs without compression. Does a userdb_mail entry override global zlib_save? (I'm about to test that, but duh, I am asking first.)

Thanks.

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