So, I'm still planning on getting v2.2.0 out Really Soon now. Unfortunately I've had to quickly develop some rather large features still at this stage. I was initially planning on leaving them for v2.3, but they were a requirement for one project and implementing them now to v2.2 was the least amount of trouble for me.
(And yes, I'm aware I haven't replied to a lot of emails in this list. There are about 60 unread ones. Hopefully I'll have time to go through them this week.)
So, what we have now:
dsync can sync ACLs
dsync can sync Sieve scripts - Slightly unfinished patch for Pigeonhole at http://dovecot.org/patches/2.2/doveadm-sieve-plugin.diff
dsync does the ACL/Sieve syncing by having implemented generic mailbox attribute syncing. (The ACLs/Sieve scripts are transparently mapped into the attribute hierarchy.) ACL plugin also supports now restricting attribute set/get/iteration. IMAP METADATA extension can be implemented using mailbox attributes. The dsync/ACL support was the main reason why I had planned on delaying native IMAP METADATA support until v2.3, but there's really no reason for that anymore. So expect IMAP METADATA support also early in v2.2.x (disabled by default). I'll still need to figure out how to do quota for it.
LDAP values can now have DN pointers to other entries that are queried. (Support for LDAP URLs could probably also be added with little trouble.) The configuration becomes a bit more complex again, but until the whole LDAP configuration is redesigned this will work. Example:
user_attrs =
=user=%{ldap:uid},
@mail=%{ldap:mailDN},
=uid=%{ldap:uidNumber@mail},
=gid=%{ldap:gidNumber@mail},
=home=%{ldap:rootPath@mail}/%d/%n