Log Message:
dovecot2: updated to 2.3.19

v2.3.19

+ Added mail_user_session_finished event, which is emitted when the mail
  user session is finished (e.g. imap, pop3, lmtp). It also includes
  fields with some process statistics information.
  See https://doc.dovecot.org/admin_manual/list_of_events/ for more
  information.
+ Added process_shutdown_filter setting. When an event matches the filter,
  the process will be shutdown after the current connection(s) have
  finished. This is intended to reduce memory usage of long-running imap
  processes that keep a lot of memory allocated instead of freeing it to
  the OS.
+ auth: Add cache hit indicator to auth passdb/userdb finished events.
  See https://doc.dovecot.org/admin_manual/list_of_events/ for more
  information.
+ doveadm deduplicate: Performance is improved significantly.
+ imapc: COPY commands were sent one mail at a time to the remote IMAP
  server. Now the copying is buffered, so multiple mails can be copied
  with a single COPY command.
+ lib-lua: Add a Lua interface to Dovecot's HTTP client library. See
  https://doc.dovecot.org/admin_manual/lua/ for more information.
- auth: Cache lookup would use incorrect cache key after username change.
- auth: Improve handling unexpected LDAP connection errors/hangs.
  Try to fix up these cases by reconnecting to the LDAP server and
  aborting LDAP requests earlier.
- auth: Process crashed if userdb iteration was attempted while auth-workers
  were already full handling auth requests.
- auth: db-oauth2: Using %{oauth2:name} variables caused unnecessary
  introspection requests.
- dict: Timeouts may have been leaked at deinit.
- director: Ring may have become unstable if a backend's tag was changed.
  It could also have caused director process to crash.
- doveadm kick: Numeric parameter was treated as IP address.
- doveadm: Proxying can panic when flushing print output. Fixes
  Panic: file ioloop.c: line 865 (io_loop_destroy): assertion failed:
  (ioloop == current_ioloop).
- doveadm sync: BROKENCHAR was wrongly changed to '_' character when
  migrating mailboxes. This was set by default to %, so any mailbox
  names containing % characters were modified to "_25".
- imapc: Copying or moving mails with doveadm to an imapc mailbox could
  have produced "Error: Syncing mailbox '[...]' failed" Errors. The
  operation itself succeeded but attempting to sync the destination
  mailbox failed.
- imapc: Prevent index log synchronization errors when two or more imapc
  sessions are adding messages to the same mailbox index files, i.e.
  INDEX=MEMORY is not used.
- indexer: Process was slowly leaking memory for each indexing request.
- lib-fts: fts header filters caused binary content to be sent to the
  indexer with non-default configuration.
- doveadm-server: Process could hang in some situations when printing
  output to TCP client, e.g. when printing doveadm sync state.
- lib-index: dovecot.index.log files were often read and parsed entirely,
  rather than only the parts that were actually necessary. This mainly
  increased CPU usage.
- lmtp-proxy: Session ID forwarding would cause same session IDs being
  used when delivering same mail to multiple backends.
- log: Log prefix update may have been lost if log process was busy.
  This could have caused log prefixes to be empty or in some cases
  reused between sessions, i.e. log lines could have been logged for the
  wrong user/session.
- mail_crypt: Plugin crashes if it's loaded only for some users. Fixes
  Panic: Module context mail_crypt_user_module missing.
- mail_crypt: When LMTP was delivering mails to both recipients with mail
  encryption enabled and not enabled, the non-encrypted recipients may
  have gotten mails encrypted anyway. This happened when the first
  recipient was encrypted (mail_crypt_save_version=2) and the 2nd
  recipient was not encrypted (mail_crypt_save_version=0).
- pop3: Session would crash if empty line was sent.
- stats: HTTP server leaked memory.
- submission-login: Long credentials, such as OAUTH2 tokens, were refused
  during SASL interactive due to submission server applying line length
  limits.
- submission-login: When proxying to remote host, authentication was not
  using interactive SASL when logging in using long credentials such as
  OAUTH2 tokens. This caused authentication to fail due to line length
  constraints in SMTP protocol.
- submission: Terminating the client connection with QUIT command after
  mail transaction is started with MAIL command and before it is
  finished with DATA/BDAT can cause a segfault crash.
- virtual: doveadm search queries with mailbox-guid as the only parameter
  crashes: Panic: file virtual-search.c: line 77 (virtual_search_get_records):
  assertion failed: (result != 0)