We are pleased to release v2.3.17 of Dovecot.

Please note that 2.3.17 release will be the last one to support Debian/Stretch since Bullseye is now supported.

https://dovecot.org/releases/2.3/dovecot-2.3.17.tar.gz
https://dovecot.org/releases/2.3/dovecot-2.3.17.tar.gz.sig
Binary packages in https://repo.dovecot.org/
Docker images in https://hub.docker.com/r/dovecot/dovecot

Regards
Aki Tuomi
Open-Xchange oy

---

* Dovecot now logs a warning if time seems to jump forward at least
  100 milliseconds.
* dict: Lines logged by the dict process now contain the dict name as
  the prefix.
* lib-index: mail_cache_fields, mail_always_cache_fields and
  mail_never_cache_fields now verifies that the listed header names are
  valid. Especially the UTF8 "–" character has sometimes been wrongly
  used instead of the ASCII "-".
+ *-login: Added login_proxy_rawlog_dir setting to capture
  rawlogs between proxy and backend.
+ dict: The server process now keeps the last 10 idle dict backends
  cached for maximum of 30 seconds. Practically this acts as a
  connection pool for dict-redis and dict-ldap. Note that this doesn't
  affect dict-sql, because it already had its own internal cache.
+ doveadm: New stats add/remove commands added to support changing the
  metrics configuration on runtime.
+ lazy_expunge: Added lazy_expunge_exclude settings to disable
  lazy_expunge for specific folders. \Special-use flags can be used as
  folder names.
+ lib-lua: Added a new helper function dovecot.restrict_global_variables()
  to disable or enable defining new global variables.
- LAYOUT=index List index rebuild was missing.
- LAYOUT=index: Duplicate GUIDs were not detected.
- acl: When using acl_ignore_namespace Dovecot attempted to access or
  create dovecot-acl-list even when the namespace should have been
  ignored. For virtual namespaces this could have yielded errors about
  "Read-only file system" or "Permission denied".
- auth: Setting the "master" passdb field to empty value would
  cause proxying to fail with an authentication error.
  Now an empty "master" field is ignored.
- doveadm-server: Duplicate error lines were sent for failed commands.
  This didn't normally cause visible problems, except when using
  wildcards in usernames or -A parameter to go through multiple users.
- doveadm-server: Logs written by doveadm-server were often missing log
  prefixes, especially mail_log_prefix for mail commands. Logs sent to
  doveadm TCP client were also missing log prefixes.
- doveadm: v2.3 regression: batch command always crashes.
- doveadm: v2.3.11 regression: Commands failed if ssl_cert or
  ssl_key files weren't readable by the user running doveadm, even
  though doveadm didn't actually use these settings
- imap-hibernate: Process may crash at deinit:
  Panic: file ioloop.c: line 928 (io_loop_destroy): assertion failed:
  (ioloop->cur_ctx == NULL).
- imap: Using imap_fetch_failure=no-after can cause assert-crash
  with some IMAP commands if reading the mail fails (e.g. wrong cached
  mail size). Fixes:
  Panic: file index-mail-headers.c: line 198 (index_mail_parse_header_init):
  assertion failed: (!mail->data.header_parser_initialized)
- imap: v2.3.10 regression: When using INDEXPVT to enable private
  \Seen flags (for shared or public namespaces) the STORE command did
  not send untagged replies for the \Seen flag changes.
- imap: v2.3.15 regression: If PREVIEW/SNIPPET is not the final FETCH
  option in the command, the IMAP FETCH response is broken.
- imap: v2.3.15 regression: MOVE command leaks mailbox if it can't be
  opened and crashes at deinit:
  Panic: file mail-user.c: line 229 (mail_user_deinit): assertion failed:
  ((*user)->refcount == 1).
- imapc: Copying nonexistent mail via imapc could have crashed. Fixes:
  Panic: file mail-storage.c: line 2385 (mailbox_transaction_commit_get_changes):
  assertion failed: (ret < 0 || seq_range_count(&changes_r->saved_uids) == save_count ||
  array_count(&changes_r->saved_uids) == 0).
- indexer: v2.3.15 regression: Process crashes if indexer-client
  disconnects while it's waiting for command reply. This happened for
  example if IMAP SEARCH triggered long fts indexing and the IMAP
  client disconnected while waiting for the reply.
- indexer: v2.3.15 regression: Process may have crashed in some situations.
- indexer: v2.3.15 regression: indexer-worker processes may not have
  reached the process_limit in some situations, possibly even using just
  one indexer-worker process even though there were many indexing
  requests queued.
- lib-compression: Reading lz4 compressed mdbox mails may crash. Fixes:
  Panic: file istream.c: line 345 (i_stream_read_memarea):
  assertion failed: (!stream->blocking).
- lib-compression: bench-compress crashes due to xz being read-only.
- lib-lua: Fix linking libdict_lua for non-GNU linkers when Lua support
  is disabled.
- lib-mail: There was no limit on how large an email header name could be.
  Processable header names are now limited to 1000 bytes.
- lib-oauth2: Dovecot disallowed JWT tokens if their validity time was
  older than token creation time (nbf < iat).
- lib-storage: Reduce memory footprint of certain storage operations.
- lib-storage: When listing mailboxes with storage name escape
  characters (^ or .) as part of the mailbox name, the listing could
  show corrupted mailbox names. Due to an issue in handling escaped
  parent folders, the listing of other mailbox names would become
  corrupted by prepending parts of the previously listed mailboxes
  parent folder as prefix to the actual mailbox names. The corruption
  can occur when using LAYOUT=INDEX and maildir or obox, or when using
  the listescape plugin.
- mail-crypt: Fix "-O" argument for "doveadm mailbox cryptokey password"
  command to be a boolean, and not expect a string.
- submission-login: Add support for not authenticating to next hop in
  submission proxying.
- submission-login: EHLO was not sent again after XCLIENT when doing
  submission proxying.
- virtual: Mailboxes do not correctly detect underlying mailboxes
  getting re-created even though they have a different UIDVALIDITY or
  GUID.