Log Message:
dovecot2: updated to 2.3.4

2.3.4:
 * The default postmaster_address is now "postmaster@<user domain or
   server hostname>". If username contains the @domain part, that's
   used. If not, then the server's hostname is used.
 * "doveadm stats dump" now returns two decimals for the \ 
"avg" field.

 + Added push notification driver that uses a Lua script
 + Added new SQL, DNS and connection events.
   See https://wiki2.dovecot.org/Events
 + Added "doveadm mailbox cache purge" command.
 + Added events API support for Lua scripts
 + doveadm force-resync -f parameter performs "index fsck" while opening
   the index. This may be useful to fix some types of broken index files.
   This may become the default behavior in a later version.
 - director: Kicking a user crashes if login process is very slow
 - pop3_no_flag_updates=no: Don't expunge DELEted and RETRed messages
   unless QUIT is sent.
 - auth: Fix crypt() segfault with glibc-2.28+
 - imap: Running UID FILTER script with errors assert-crashes
 - dsync, pop3-migration: POP3 UIDLs weren't added to
   dovecot.index.cache while mails were saved.
 - dict clients may have been using 100% CPU while waiting for dict
   server to finish commands.
 - doveadm user: Fixed user listing via HTTP API
 - All levels of Cassandra log messages were logged as Dovecot errors.
 - http/smtp client may have crashed after SSL handshake
 - Lua auth converted strings that looked like numbers into numbers.