Changes to the Cyrus IMAP Server since 2.4.17-caldav-beta9

      * DAV DB changes now occur in the mailbox API which means that
        replication works for calendars and addressbooks. 
      * IMAP XFER is now based on replication. 
      * Added support for free/busy query URL to CalDAV. 
      * Authentication for GET/HEAD requests is now done on-demand so that
        free/busy queries and/or calendar subscriptions can be done
        anonymously (subject to ACL). 
      * Added support for VAVAILABILITY, VPOLL, RSCALE to CalDAV based on
        current drafts (requires libical from git). 
      * Updated http_timezone.c to be compliant with current draft. 
      * Numerous other CalDAV fixes/enhancements. 

Changes to the Cyrus IMAP Server since 2.4.17-caldav-beta8

      * Fixed bug in parsing of Accept header (now accepts */* and type/*). 
      * Fixed telemetry logging bug (old garbage appearing in log). 
      * Added a workaround for the DELETE bug in MacOS X 10.9.0 Calendar
        client. 

Changes to the Cyrus IMAP Server since 2.4.17-caldav-beta7

      * Added Timzone Service module along with associated admin tools
        (ctl_zoneinfo, vzic). 
      * Added support for accepting/returning jCal (requires Jansson) and
        xCal data wherever iCalendar data is allowed. 
      * Proxied responses (including chunked) are now piped to client
        rather than being buffered and forwarded. 
      * Better handling of COPY/MOVE between backends (including LOCKs). 
      * Fixed "annotation truncation" bug where the largest allowed
        annotation value was slightly less than 4k (solves problem reading
        CalDavZAP settings). 
      * GET on ./well-known now returns a list of /.well-known/ URLs on the
        server. 
      * Added support for X-HTTP-Method-Override header in POST requests. 
      * Added replacement functions for those not present in libxml2 <
        v2.8.0 
      * Plugged a few more memory leaks found by Valgrind. 

Changes to the Cyrus IMAP Server since 2.4.17-caldav-beta6

      * Plugged several memory leaks found by Valgrind 
      * Less verbose reconnect communication between frontend and backend 
      * GET on calendar-home-set now returns a list of subscribe-able
        calendars 
      * Auto-provisioning of calendars/addressbooks now works via a
        frontend proxy 
      * Fixed several conformance bugs detected by CalDAVTester 
      * Added support for optionally adding Content-MD5 header to responses
        (see httpcontentmd5 option) 
      * Fixed time-based queries for components other than VEVENT 

Changes to the Cyrus IMAP Server since 2.4.17-caldav-beta5

      * RSS module now produces Atom 1.0 output rather than RSS 2.0 (we
        prefer IETF standards) 
      * PROPFIND/REPORT allprop/propname requests are now supported 
      * unixhierarchysep is now supported by all HTTP modules 
      * Completely rewrote write_body() - Range requests are now supported
        on non-chunked Content-Encoded data 
      * Added cache control response headers where appropriate to make
        Redbot happy 
      * Fixed handling of telemetry log file descriptors and truncation 
      * Allow GET on calendar collections for "exporting" entire calendar 
      * Fixed POST on calendar collection (add-member) 
      * Fixed parsing of calendar-query filter 
      * Added several CalDAV/iCalendar validation checks based on
        CalDAVTester results 

Changes to the Cyrus IMAP Server since 2.4.17-caldav-beta4

      * Always verify authorization credentials supplied by the client (a
        proxy may be reusing an existing connection as a different user) 
      * Don't bother supporting Digest qop=auth-int since no clients seem
        to use it 
      * Don't show addressbook mailboxes in IMAP LIST output 
      * Plugged leaked memory found by Valgrind 
      * Better handling of request/response bodies 
      * Added httpprettytelemetry option 
      * Added httpallowcors option (Cross-Origin Resource Sharing) 

Changes to the Cyrus IMAP Server since 2.4.17-caldav-beta3

      * Plugged leaked memory found by Valgrind 
      * Rewrote list_feeds() to not use memmem() 
      * OPTIONS method can be used without authentication 
      * Better handling of Connection:keep-alive 
      * Added httpallowedurls option 

Changes to the Cyrus IMAP Server since 2.4.17-caldav-beta2

      * Fixed security bug where a user-agent could access files outside of
        httpdocroot. 
      * Changed annotation entry name scheme to be
