v2.4.4 2026-05-06  Aki Tuomi <aki.tuomi@open-xchange.com>

	* CVE-2026-27851: lib-var-expand: Safe filter marks all following pipelines safe.
	* CVE-2026-33603: auth: CRAM-SHA-*-PLUS channel binding could be faked.
	  MITM attacker with a certificate trusted by the client could have
	  bypassed the requirement for channel binding.
	* CVE-2026-40020: IMAP folders can be shared-spammed to everyone.
	* CVE-2026-42006: An attacker can cause uncontrolled memory usage with
	  excessive bracing over IMAP. The fix in CVE-2026-27857 was incomplete.
	* indexer-worker, quota-status, script-login, program-client-local: Root
	  privileges are now dropped permanently before serving requests.
	* indexer-worker: Default restart_request_count changed to 1 to work
	  correctly after permanent root privilege drop.
	* lmtp: Add back service_extra_groups=$SET:default_internal_group that was
	  incorrectly removed in v2.4.3.
	* master: inet_listener_reuse_port has been replaced by service_reuse_port.
	  The new setting properly pre-creates all listener sockets at startup and
	  assigns one unique socket per process. Using this allows evenly distributing
	  incoming connections to login processes. See
	  https://doc.dovecot.org/latest/core/config/service.html#service_reuse_port
	  for details.
	- auth: Fix LDAP escaping of 0x13 control character.
	- auth: Use timing-safe comparison for certificate and public key fingerprints.
	- fts: Correctly handle internal http-client response errors.
	- fts: Don't send request to Tika if there is no body text.
	- fts: Fix address header indexing for RFC 2047 encoded-words.
	- fts: tika, fts-solr: Fix use-after-free crash during DNS lookup.
	- imap: Fix assertion panic on invalid REPLACE 0 command.
	- lib-auth-client: Avoid "unknown id" errors for aborted auth requests.
	- lib-dcrypt: Fix potential crash if trying to access untrusted/corrupted keys.
	- lib-dcrypt: Improve error message if keys aren't in hex format as expected.
	- lib-index: Fix potential crash if fsck fails.
	- lib-ldap: Fix using OpenLDAP default CA when ssl_client_ca_dir/file is unset.
	  v2.4.3 regression.
	- lib-master, master: Fix behavior for services with client_limit>1 and
	  restart_request_count so that processes reaching restart_request_count are
	  no longer counted towards process_limit.
	- lib-master: Fix crash when reaching client_limit with restart_request_count>1.
	- lib-master: haproxy - Don't trust client certificate common name when
	  HAProxy reports verification failure.
	- lib-sasl: cram-md5 - Fix out of bounds memory read.
	- lib-sasl: oauth2 - Fix one byte out of bounds read.
	- lib-sql: cassandra - Fix reusing Cassandra SSL connections.
	- lib-sql: sqlite - Fix sqlite_journal_mode=wal to actually work.
	- lib-storage: Auto-rename non-NFC subscription file entries to NFC on read.
	- lib-storage: Prevent non-atom SEARCH keywords from causing IMAP
	  command injection.
	- lib-var-expand-crypt: Return error if hex decoding fails.
	- lib-var-expand: Fix crash (SIGFPE) with non-positive divisor for / and %.
	- log: Fix memory leak at deinit.
	- login-common: When process is full, don't destroy clients waiting on
	  master auth.
	- login-proxy: Fix crash with rawlog and multiplexing during reconnection.
	- mail-compress: Fix panic when save method unavailable.
	- mail-crypt: Fix crash when HMAC-based algorithm is used.
	- mail-crypt: Use AEAD instead of HMAC with ChaCha20-Poly1305.
	- mdbox: Create files with O_NOFOLLOW.
	- push-notification: ox - Fix use-after-free crash during DNS lookup.
	- quota: quota-status - Limit input buffer size to 1 kB.

v2.4.3 2026-03-27  Aki Tuomi <aki.tuomi@open-xchange.com>

	* CVE-2025-59028: Invalid base64 authentication can cause DoS for other
	  logins.
	* CVE-2025-59031: decode2text.sh OOXML extraction may follow symlinks
	  and read unintended files during indexing. Fixed by dropping the script.
	* CVE-2026-24031: SQL injection possible if auth_username_chars is
	  configured empty. Fixed escaping to always happen. v2.4 regression.
	* CVE-2026-27859: Excessive RFC 2231 MIME parameters in email would cause
	  excessive CPU usage. Fixed by limiting number of parameters to process.
	* CVE-2026-27860: LDAP query injection possible if auth_username_chars
	  is configured empty. Fixed escaping to always happen. v2.4 regression.
	* CVE-2026-27857: Sending excessive parenthesis causes imap-login to use
	  excessive memory.
	* CVE-2026-27856: Doveadm credentials were not checked using timing-safe
	  checking function.
	* CVE-2026-27855: OTP driver vulnerable to replay attack.
	* Remove default service/*/service_extra_groups=$SET:default_internal_group.
	  They are now replaced by default mail_access_groups=$SET:default_internal_group.
	* The version file has been renamed as version.txt to avoid clash with
	  C++ headers.
	* auth: oauth2 - Do not export token automatically, must be exported using
	  fields.
	* config: Don't accept 0 as meaning unlimited anymore for
	  last_valid_uid, last_valid_gid, mail_cache_max_headers_count,
	  mail_cache_max_header_name_length, mail_vsize_bg_after_count,
	  mail_sort_max_read_count, message_max_size, submission_max_recipients
	  and quota_mail_size.
	* imap, pop3: Don't autoexpunge if Dovecot is shutting down or process
	  is killed.
	* imap: LIST - Handle invalid mUTF-7 mailbox names as never matching anything
	* lazy-expunge: Change lazy_expunge_only_last_instance default to yes.
	* lda: Use EX_TEMPFAIL (75) if configuration is invalid instead of 89.
	  v2.4 regression.
	* lib-master: Increase ANVIL_DEFAULT_LOOKUP_TIMEOUT_MSECS from 5s to 30s
	* lib: crc32 - Use zlib's built-in CRC32 function
	+ Improve UTF-8 support for mail storage.
	+ auth: Add default auth-token UNIX socket for token-based authentication.
	+ doc: solr-config-9.xml - Make it compatible with Solr 9.8.0
	+ doveadm: dsync - Search mails when exporting to reduce number of mails
	  exported by dsync-server.
	+ dovecot-sysreport: Add -D|--destdir support.
	+ imap, imap-hibernate: Use DOVECOT-TOKEN authentication for unhibernation.
	  Default imap-master socket permissioms have been changed due to this.
	+ imap: Add APPENDLIMIT capability when configured with quota_mail_size.
	+ imap: Support STATUS (DELETED) for IMAP4rev2.
	+ imapc: Add support for SEARCH MIMEPART
	+ imapc: Improve error forwarding.
	+ imapc: Support SORT and ESORT extensions.
	+ imapc: Support STATUS (DELETED) for IMAP4rev2.
	+ lib-sql: Support parameterized queries.
	+ lib-test: Add new test-dir API for better temporary test directory
	  handling.
	+ lmtp: Advertize SIZE capability when configured with quota_mail_size.
	+ lmtp: Support XCLIENT DESTADDR and DESTPORT
	+ pop3-login: proxy - Add support for XCLIENT DESTIP and DESTPORT
	+ submission-login: proxy - Add support for XCLIENT DESTIP and DESTPORT
	+ Various optimizations have been made to the code.
	- Fix building dovecot with BSD, Solaris and macOS.
	- auth: Crash would occur if users were iterated but
	  userdb_ldap_iterate_fields was not set.
	- auth: Fix request leak when client authenticates with unsupported mechanism.
	- auth: Some passdbs would default to PLAIN instead of CRYPT scheme.
	- config: Section and setting names could have been intermixed, resulting
	  in the setting being silently ignored.
	- configure: Fix checking if BUILD_IMAP_HIBERNATE is set
	- doveadm: dsync - -e parameter was handled wrong with dsync-server.
	- fts-flatcurve: Mailbox leak would occur if mailbox failed to open.
	- imap: Fix potential issues with unhibernation and process state handling.
	- imapc: SEARCH failure handling was done wrong.
	- imapc: UID STORE commands included extra comma in uidset.
	- lib-auth-client: auth-master - Fix panic when reconnecting after
	  handshake timeout.
	- lib-compression: Lz4 algorithm would assert-crash with malicious data.
	- lib-dcrypt: Fix digest algorithm handling.
	- lib-dict: Escape username paths to prevent traversal issues with dict-fs.
	- lib-http: Fix HTTP parsing edge cases and state handling.
	- lib-iostream: Disallow empty ssl_min_protocol.
	- lib-json: Fix incorrect character handling logic.
	- lib-ldap: Fix various TLS related bugs.
	- lib-mail: Fix charset translation and MIME parsing edge cases.
	- lib-mail: Fix multiple bounds checks and parsing issues in message handling.
	- lib-var-expand: Multiple fixes and improvements for expansion handling.
	- lib: Fix punycode decoding out-of-bounds reads.
	- lib: Fix unicode normalization edge cases causing crashes.
	- lib-http: Chunked transfer trailer size was not limited.
	- login-common: Improve logging and internal error handling.
	- login-common: login_log_format_elements was split by spaces naively, which
	  could break variable expansion. Use template aware splitting now.
	- master: Dovecot would fail to start if listen directive was used and
	  dovenull or dovecot user was missing.
	- pop3c: Connection might've hung with SSL.
	- util: Fix handling of environment variables containing control characters.
	- Many other bugs have been fixed.

v2.4.2 2025-10-24  Aki Tuomi <aki.tuomi@open-xchange.com>

	* CVE-2025-30189: Passdb oauth2 (not oauth2 mechanism), passdb passwd,
	  passdb bsdauth, and userdb passwd drivers would cause users to be
	  cached with same cache key when auth cache was enabled.
	* auth: Remove proxy_always field.
	* config: Change settings history parsing to use python3.
	* doveadm: Print table formatter - Print empty values as "-".
	* imapc: Propagate remote error codes properly.
	* lda: Default mail_home=$HOME environment if not using userdb lookup
	* lib-dcrypt: Salt for new version 2 keys has been increased to 16 bytes.
	* lib-dregex: Add libpcre2 based regular expression support to Dovecot,
	  if the library is missing, disable all regular expressions. This
	  adds libpcre2-32 as build dependency.
	* lib-oauth2: jwt - Allow nbf and iat to point 1 second into future.
	* lib: Replace libicu with our own unicode library. Removes libicu as build
	  dependency.
	* login-common: If proxying fails due to remote having invalid SSL cert, don't reconnect.
	+ auth: Add ssl_client_cert_fp and ssl_client_cert_pubkey_fp fields, see
	  https://doc.dovecot.org/latest/core/summaries/settings.html#ssl_peer_certificate_fingerprint_hash
	  for more information.
	+ config: Add support for $SET:filter/path/setting.
	+ config: Improve @group includes to work with overwriting their settings.
	+ doveadm kick: Add support for kicking multiple usernames
	+ doveadm mailbox status: Add support for deleted status item.
	+ imap, imap-client: Add experimental partial IMAP4rev2 support.
	+ imap: Implement support for UTF8=ACCEPT for APPEND
	+ lib-oauth2, oauth2: Add oauth2_token_expire_grace setting.
	+ lmtp: lmtp-client - Support command pipelining.
	+ login-common: Support local/remote blocks better.
	+ master: accept() unix/inet connections before creating child process
	  to handle it. This reduces timeouts when child processes are slow to
	  spawn themselves.
	- SMTPUTF8 was accepted even when it wasn't enabled.
	- auth, *-login: Direct logging with -L parameter was not working.
	- auth: Crash occured when OAUTH token validation failed with
	  oauth2_use_worker_with_mech=yes.
	- auth: Invalid field handling crashes were fixed.
	- auth: ldap - Potential crash could happen at deinit.
	- auth: mech-gssapi - Server sending empty initial response would cause
	  errors.
	- auth: mech-winbind - GSS-SPNEGO mechanism was erroneously marked as
	  not accepting NUL.
	- config: Multiple issues with $SET handling has been fixed.
	- configure: Building without LDAP didn't work.
	- doveadm: If source user didn't exist, a crash would occur.
	- imap, pop3, submission, imap-urlauth: USER environment usage was broken
	  when running standalone.
	- imap-hibernate: Statistics would get truncated on unhibernation.
	- imap: "SEARCH MIMEPART FILENAME ENDS" command could have accessed
          memory outside allocated buffer, resulting in a crash.
	- imapc: Fetching partial headers would cause other cached headers to
	  be cached empty, breaking e.g. imap envelope responses when caching to disk.
	- imapc: Shared namespace's INBOX mailbox was not always uppercased.
	- imapc: imapc_features=guid-forced GUID generation was not working correctly.
	- lda: USER environment was not accepted if -d hasn't been specified.
	- lib-http: http-url - Significant path percent encoding through parse
	  and create was not preserved. This is mainly important for Dovecot's
	  Lua bindings for lib-http.
	- lib-settings: Crash would occur when using %variables in SET_FILE type settings.
	- lib-storage: Attachment flags were attempted to be added for
	  readonly mailboxes with mail_attachment_flags=add-flags.
	- lib-storage: Root directory for unusable shared namespaces was
	  unnecessarily attempted to be created.
	- lib: Crash would occur when config was reloaded and logging to syslog.
	- login-common: Crash might have occured when login proxy was destroyed.
	- sqlite: The sqlite_journal_mode=wal setting didn't actually do anything.
	- Many other bugs have been fixed.

v2.4.1 2025-03-28  Aki Tuomi <aki.tuomi@open-xchange.com>

	* auth: Change unix_listener/auth-userdb/group = $SET:default_internal_group
	  This change needs dovecot_config_version=2.4.1.
	* auth: lua - Remove support for single string result.
	* imap: Unconditionally advertise SPECIAL-USE capability.
	* lib-dcrypt: Install dcrypt_openssl.so into dovecot modules directory.
	* lib-master: For glibc, default MALLOC_MMAP_THRESHOLD_=131072.
	* lib-storage: Change default mail_cache_fields to:
	  hdr.date hdr.subject hdr.from hdr.sender hdr.reply-to hdr.to
	  hdr.cc hdr.bcc hdr.in-reply-to hdr.message-id
	  date.received size.virtual imap.bodystructure mime.parts hdr.references
	  hdr.importance hdr.x-priority hdr.x-open-xchange-share-url
	  pop3.uidl pop3.order. This change needs dovecot_config_version=2.4.1.
	* lib-var-expand: Use moduledir instead of pkglibdir for crypt.
	* lmtp: Change the default lmtp_user_concurrency_limit to 10.
	  This change needs dovecot_config_version=2.4.1.
	* lmtp: Change the default service_restart_request_count to 1.
	  This change needs dovecot_config_version=2.4.1.
	+ auth: Allow configuring passdb/userdb sql to use auth-workers.
	+ config: Add default group @mailbox_defaults = english.
	+ config: Improve "Unknown setting" error with more details and
	  suggestions.
	+ doveconf: Add -U parameter to ignore unknown settings in config file.
	+ fts-flatcurve: Support lock files in VOLATILEDIR.
	+ imap-acl: Add support for the IMAP LIST-MYRIGHTS capability (RFC 8440).
	+ imap-client: Support ANONYMOUS authentication.
	+ imap: Implement support for the REPLACE capability.
	- auth: ldap - Passdb fields were ignored with
	  passdb_ldap_bind_userdn=yes.
	- auth: lua - Fix error result handling in lua passdb/userdb.
	- auth: oauth2 - When building oauth2 failure reply, memory would leak.
	- config: local_name handling would work wrong with multiple names and
	  wildcards.
	- fts-flatcurve: A potential crash could occur when searching virtual
	  mailboxes.
	  Fixes: Panic: file fts-search.c: line 87 (level_scores_add_vuids):
	  assertion failed: (array_count(&vuids_arr) == array_count(&br->scores))
	- fts-flatcurve: Maybe queries were done wrong.
	- fts-flatcurve: Non-selectable mailboxes were not ignored when doing
	  optimize/rescan.
	- fts-flatcurve: Signal 11 crash could happen with fts rescan.
	- fts: Fix crash caused by event object lifecycle mishandling.
	- imap-hibernate: Client counters would get reset on unhibernation,
	  affecting imap_logout_format variables.
	- imap: Crash would occur with Maildir when trying to send INPROGRESS
	  during mailbox syncing.
	- ldap: Dovecot could not be compiled without LDAP.
	- lib-dcrypt: Output stream encryption can cause assert crash if
	  attempting to encrypt over 64 GiB of data with GCM. This is still not
	  supported with GCM, but it fails better.
	- lib-http: HTTP client context memory usage was increasing.
	- lib-http: Pipeline corruption could happen after 100 Continue response.
	- lib-settings: Variable expansion initialization could crash with
	  Panic: file settings.c: line 1560 (settings_var_expand_init_add):
	  assertion failed: (I_MAX(num_tables, num_provs) == num_ctx)
	- lib-smtp: Pipelining initial SASL response after AUTH was broken.
	- lib-var-expand: If filter failed, memory leak would occur.
	- lib-var-expand: Older bison versions did not have error symbol for
	  handling causing unexpected behaviour on the parser on error conditions.
	- quota: Quota calculations had minor bugs causing small errors.

v2.4.0 2025-01-24  Aki Tuomi <aki.tuomi@open-xchange.com>

	* config: dovecot_config_version must be the first non-comment
	  line in configuration file.
	* config: dovecot_storage_version must be in the configuration
	  file.
	* config: Many configuration options have changed so old configuration
	  files do not work without rewrite. See
	  https://doc.dovecot.org/main/installation/upgrade/2.3-to-2.4.html
	* config: New variable expansion syntax has been introduced, see
	  https://doc.dovecot.org/main/core/settings/variables.html
	* config: Some default settings have changed.
	* config: plugin {} section has been removed.
	* *-login: With ssl=required, connections from login_trusted_networks
	  are now also required to be SSL/TLS encrypted.
	* acl: Use ACL settings instead of Global ACL Directories.
	* auth-worker: auth_worker_max_count is replaced with
	  service auth-worker { process_limit }.
	* auth: Weak password schemes are disabled by default, use
	  auth_allow_weak_schemes to enable them.
	* auth_debug, mail_debug: Use log_debug filter instead.
	* config: All sections require a name, for example passdb/userdb:
	  passdb static {
	     password=secret
	   }
	* db2: Remove Berkeley DB support.
	* dict-memcached: This is removed, use Redis instead.
	* director: Feature has been removed. See potential replacement at
	  https://github.com/dovecot/tools/blob/main/director.lua
	* doveadm: USER environment variable is only supported with
	  --no-userdb-lookup. One of -u, -F or -A must be used
	  otherwise.
	* doveconf: Option -n is now default when running doveconf.
	* dsync: Use doveadm sync instead, legacy symlink has been removed.
	* fs-sis: Feature is now deprecated and has been made read-only.
	  It will be removed in future release.
	* fts-lucene, fts-squat: These have been removed, use fts-flatcurve or
	  fts-solr instead.
	* imap-login: IMAP compression is now handled in proxies.
	* imap_quota: SETQUOTA / quota_set has been removed.
	* imap_zlib: This plugin is no longer needed, it's always enabled.
	* imapc: All features are enabled by default, imapc_features can be used
	  to explicitly disable features that are not wanted.
	* lib-storage: mbox driver is now frozen.
	* mail_compress: XZ and LZMA algorithm support has been removed.
	* mailbox-alias: Plugin has been removed.
	* old_stats, auth_stats: These have been removed.
	* openssl: Minimum supported version of OpenSSL is now 1.1.1.
	* openssl: Add support for OpenSSL 3.x
	* quota-dict, quota-dirsize: These have been removed, use quota-count
	  instead. You can use quota_clone to copy quota usage to some database.
	* replicator: Feature has been removed. Use NFS or some other shared
	  filesystem instead, or run doveadm sync in crontab.
	* stats: The bytes_in and bytes_out field in several events have been
	  renamed as net_in_bytes and net_out_bytes.
	* zlib: Renamed to mail_compress plugin.
	+ Experimental SMTPUTF8 and IMAP UTF8=ACCEPT support has been added.
	  Needs --enable-experimental-mail-utf8 configure option and
	  mail_utf8_extensions=yes setting.
	+ Long running mail commands can be aborted with Ctrl-C / doveadm kick.
	+ auth: LDAP driver now supports multi-value attributes.
	+ auth: Add support for SCRAM-SHA-1-PLUS and SCRAM-SHA-256-PLUS.
	+ auth: Add support for TLS channel binding.
	+ auth: Support sending JA3 hash to policy server.
	+ configure: Detect latest Lua version.
	+ *-login: Support for TLS Server Name has been improved to allow pre-login
	  settings. For example capabilities to be changed based on TLS Server Name.
	+ *-login: Support for TLS ALPN has been added, connections with mismatching
	  application are now refused. Missing ALPN is accepted.
	+ fts-flatcurve: New Xapian based FTS plugin has been added.
	+ imap: Support for INPROGRESS untagged messages as per RFC 9585.
	+ lib-lua: Expose Dovecot DNS client.
	+ lib-lua: Expose Dovecot HTTP client.
	+ lib-sasl: Support SCRAM-SHA mechanisms.
	+ lmtp: SNI support has been added which allows settings to be applied
	  based on TLS Server Name.
	+ sqlite: Support WAL mode.
	+ stats: Submetric name size has been increased.
	+ submission: Add submission_add_received_header setting to protect
	  sender identity by suppressing the Received: header.
	- Many bugs have been fixed.

v2.3.21.1 2024-08-14  Aki Tuomi< aki.tuomi@open-xchange.com>

	- CVE-2024-23184: A large number of address headers in email resulted
	  in excessive CPU usage.
	- CVE-2024-23185: Abnormally large email headers are now truncated or
	  discarded, with a limit of 10MB on a single header and 50MB for all
	  the headers of all the parts of an email.
	- oauth2: Dovecot would send client_id and client_secret as POST parameters
	  to introspection server. These need to be optionally in Basic auth
	  instead as required by OIDC specification.
	- oauth2: JWT key type check was too strict.
	- oauth2: JWT token audience was not validated against client_id as
	  required by OIDC specification.
	- oauth2: XOAUTH2 and OAUTHBEARER mechanisms were not giving out
	  protocol specific error message on all errors. This broke OIDC discovery.
	- oauth2: JWT aud validation was not performed if aud was missing
	  from token, but was configured on Dovecot.

v2.3.21 2023-09-15  Aki Tuomi <aki.tuomi@open-xchange.com>

	* lib-oauth2: Allow JWT tokens to be validated with missing typ field.
	  The typ field is left out by some key issuers to conserve space,
	  notably kubernetes. Now missing typ is tolerated, but if present, it
	  still must be "jwt".
	+ auth: Auth passdb and userdb reply can contain "event_<name>=value"
	  which will be added to login event and mail user event respectively.
	+ lib-master: Set process title during various initialization stages to
	  clearly describe what the process is waiting on.
	+ lib-storage: The mail_temp_scan_interval is now fuzzed incrementing it
	  by 0..30% based on username's hash to reduce the chance of load spikes.
	+ lib-storage: The temp file scan has been moved from the open of the
	  mailbox to the close, to reduce the latency perceived by users.
	+ stats: If metric has fields specified, all these fields are
	  exported as counters to prometheus exposition.
	  See https://doc.dovecot.org/configuration_manual/stats/openmetrics/.
	- *-login: Processes might have crashed when a SSL connection disconnects
	  uncleanly.
	- acl: When plugin was loaded \HasChildren and \HasNoChildren flags
	  were calculated incorrectly for mailboxes containing '*' and '%'
	  in their names.
	- auth: Crash occured if a connection to PostgreSQL database server
	  failed during startup.
	- auth: Logins with invalid passwords (e.g. unknown scheme) in passdb
	  were failing with "password mismatch" instead of "internal error".
	- auth: XOAUTH2 and OAUTHBEARER mechanisms were not giving out protocol
	  specific error message on all errors. This especially broke OIDC
	  discovery.
	- dbox: When last_temp_file_scan header wasn't set (especially after
	  dsync migration), the next mailbox open always triggers the temp file
	  scan. This could have caused a load spike after migrations. Fixed by
	  using the mailbox directory's atime when the header isn't set, which
	  usually moves the scan time into the future.
	- dict-redis: A crash would occur on transaction rollback.
	- dsync: Infinite loop causing out of memory would occur when handling
	  mailbox deletion from remote end and hierarchy separators would differ.
	- dsync: Incremental dsync failed for folder names ending with '%',
	  unless BROKENCHAR was set. Also folder names with '%' elsewhere in
	  them caused each incremental dsync to unnecessarily rename the folder
	  to a temporary name and back. v2.3.19 regression.
	- imap-hibernate: If an IMAP client unhibernation timed out with
	  "(version received)", the unhibernation could still have successfully
	  finished later on and continued working normally. This was rather
	  confusing, because imap-hibernate already logged that the client got
	  disconnected. Avoid this by forcing the connection to shutdown on
	  unhibernation timeout.
	- imapc: Crashed when a folder mapped through the virtual plugin
	  disappears from the storage.
	- imapc: EXPUNGE, EXISTS or FETCH replies from a server for a previously
	  selected mailbox could have been processed as if they belonged to the
	  new mailbox currently being selected. This could have caused warnings.
	- lib-http: Dovecot HTTP server (doveadm, stats/openmetrics) may have
	  disconnected HTTP clients before the response is fully sent. This
	  happened only on busy servers where kernel's socket buffers were
	  rather full.
	- lib-http: Fixed a potential crash on http-server if a client
	  disconnected early. v2.3.18 regression.
	- lib-index: Index file corruption could have caused a crash. Fixes:
	  Panic: file mail-transaction-log-view.c: line 165 (mail_transaction_log_view_set):
	  assertion failed: (min_file_seq <= max_file_seq).
	- lib-index: Purging an existing >1GB cache file can crash. Now cache
	  files still above 1GB after purging are removed. Fixes:
	  Panic: file mail-index-util.c: line 10 (mail_index_uint32_to_offset):
	  assertion failed: (offset < 0x40000000)
	- lib-lua: A HTTP client could not resolve DNS names in mail processes,
	  because it expected "the dns-client" socket to exist in the current
	  directory.
	- lib-oauth2: Dovecot would send client_id and client_secret as POST
	  parameters to the introspection server. These need to be optionally in
	  Basic auth instead.
	- lib-oauth2: JWT aud validation was not performed if aud was missing
	  from a token, but was configured on Dovecot.
	- lib-oauth2: JWT key type check was too strict.
	- lib-oauth2: JWT token audience was not validated against client_id as
	  required by the specification.
	- lib-ssl-iostream: Using the ssl_require_crl=yes setting may have caused
	  CRL check failures for outgoing SSL/TLS connections, although it was
	  supposed to affect checking CRLs only for client-side SSL
	  certificates. v2.3.17 regression.
	- lib-sql: MySQL driver leaked memory when connection failed.
	- lib-storage: Various fixes when running into out of disk space.
	- master: Service idle_kill setting didn't work properly on busy
	  servers. It was very unlikely that any process was idling long enough
	  to become killed. Also the idle_kill handling code was using quite a
	  lot of CPU on the master process when there were a lot of processes
	  (e.g. imap). The new behavior is to track the lowest number of idling
	  processes every idle_kill time interval and then kill that many idling
	  processes.
	- mdbox: Temp file scan was done for always empty directories.
	- mdbox: The fdatasync() call was done in wrong parent directory when
	  writing mails. Also on a failure it crashed instead of logging an error.
	- notify_status: The plugin crashes if any user initialization fails.
	- pop3: Sending command with the ':' character caused an assert-crash.
	  v2.3.18 regression. Fixes: Panic: event_reason_code_prefix(): name has ':'
	- stats: Fix panic when a nonexistent event exporter was referenced while
	  adding a new metric dynamically via doveadm stats add. This produces
	  a proper error now.
	- stats: If process exported a lot of events and then exited, some of
	  the last events may have become lost.
	- stats: Invalid Prometheus label names were created with specific
	  histogram group_by configurations. Prometheus rejected these labels.
	- welcome: The plugin didn't execute in some situations that created
	  INBOX but didn't open it, e.g. if GETMETADATA was used before the
	  INBOX was opened.

v2.3.20 2022-12-22  Aki Tuomi <aki.tuomi@open-xchange.com>

	+ Add dsync_features=no-header-hashes. When this setting is enabled and
	  one dsync side doesn't support mail GUIDs (i.e. imapc), there is no
	  fallback to using header hashes. Instead, dsync assumes that all mails
	  with identical IMAP UIDs contains the same mail contents. This can
	  significantly improve dsync performance with some IMAP servers that
	  don't support caching Date/Message-ID headers.
	+ lua: HTTP client has more settings now, see
	  https://doc.dovecot.org/admin_manual/lua/#dovecot.http.client
	+ replicator: "doveadm replicator status" command now outputs when the
	  next sync is expected for the user.
	- LAYOUT=index: duplicate GUIDs were not cleaned out. Also the list
	  recovery was not optimal.
	- auth: Assert crash would occur when iterating multiple userdb
	  backends.
	- director: Logging into director using master user with
	  auth_master_user_separator character redirected user to a wrong
	  backend, unless master_user_separator setting was also set to the same
	  value. Merged these into auth_master_user_separator.
	- dsync: Couldn't always fix folder GUID conflicts automatically with
	  Maildir format. This resulted in replication repeatedly failing
	  with "Remote lost mailbox GUID".
	- dsync: Failed to migrate INBOX when using namespace prefix=INBOX/,
	  resulting in "Remote lost mailbox GUID" errors.
	- dsync: INBOX was created too early with namespace prefix=INBOX/,
	  resulting a GUID conflict. This may have been resolved automatically,
	  but not always.
	- dsync: v2.3.18 regression: Wrong imapc password with dsync caused
	  Panic: file lib-event.c: line 506 (event_pop_global):
	  assertion failed: (event == current_global_event)
	- imapc: Requesting STATUS for a mailbox with imapc and INDEXPVT
	  configured did not return correct (private) unseen counts.
	- lib-dict: Process would crash when committing data to redis without
	  dict proxy.
	- lib-mail: Corrupted cached BODYSTRUCTURE caused panic during FETCH.
	  Fixes: Panic: file message-part-data.c: line 579 (message_part_is_attachment):
	  assertion failed: (data != NULL). v2.3.13 regression.
	- lib-storage: mail_attribute_dict with dict-sql failed when it tried to
	  lookup empty dict keys.
	- lib: ioloop-kqueue was missing include breaking some BSD builds.
	- lua-http: Dovecot Lua HTTP client could not resolve DNS names in mail
	  processes, because it expected "dns-client" socket to exist in the
	  current directory.
	- oauth2: Using %{oauth2:name} variables could cause useless
	  introspections.
	- pop3: Sending POP3 command with ':' character caused an assert-crash.
	  v2.3.18 regression.
	- replicator: Replication queue had various issues, potentially causing
	  replication requests to become stuck.
	- stats: Invalid Prometheus label names were created with specific
	  histogram group_by configurations. Prometheus rejected these labels.

v2.3.19.1 2022-06-14  Aki Tuomi <aki.tuomi@open-xchange.com>

	- doveadm deduplicate: Non-duplicate mails were deleted.
	  v2.3.19 regression.
	- auth: Crash would occur when iterating multiple backends.
	  Fixes: Panic: file userdb-blocking.c:
	  line 125 (userdb_blocking_iter_next): assertion failed: (ctx->conn != NULL)

v2.3.19 2022-05-10  Aki Tuomi <aki.tuomi@open-xchange.com>

	+ 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)

v2.3.18 2022-02-03  Aki Tuomi <aki.tuomi@open-xchange.com>

	* Removed mail_cache_lookup_finished event. This event wasn't especially
	  useful, but it increased CPU usage significantly.
	* fts: Don't index inline base64 encoded content in FTS indexes using
	  the generic tokenizer. This reduces the FTS index sizes by removing
	  input that is very unlikely to be searched for. See
	  https://doc.dovecot.org/configuration_manual/fts/tokenization for
	  details on how base64 is detected. Only applies when using libfts.
	* lmtp: Session IDs are now preserved through proxied connections, so
	  LMTP sessions can be tracked. This slightly changes the LMTP session
	  ID format by appending ":Tn" (transaction), ":Pn" (proxy connection)
	  and ":Rn" (recipient) counters after the session ID prefix.
	+ Events now have "reason_code" field, which can provide a list of
	  reasons why the event is happening. See
	  https://doc.dovecot.org/admin_manual/event_reasons/
	+ New events are added. See https://doc.dovecot.org/admin_manual/list_of_events/
	+ fts: Added fts_header_excludes and fts_header_includes settings to
	  specify which headers to index. See
	  https://doc.dovecot.org/settings/plugin/fts-plugin#plugin-fts-setting-fts-header-excludes
	  for configuration details.
	+ fts: Initialize the textcat language detection library only once per
	  process. This can reduce CPU usage if fts_languages setting has multiple
	  languages listed and service indexer-worker { service_count } isn't 1.
	  Only applies when using libfts.
	+ lib-storage: Reduced CPU usage significantly for some operations that
	  accessed lots of emails (e.g. fetching all flags in a folder, SORT, ...)
	+ lib: DOVECOT_PREREQ() - Add micro version which enables compiling
	  external plugins against different versions of Dovecot.
	+ lmtp: Added new lmtp_verbose_replies setting that makes errors sent to
	  the LMTP client much more verbose with details about why exactly
	  backend proxy connections or commands are failing.
	+ submission: Support implicit SASL EXTERNAL with
	  submission_client_workarounds=implicit-auth-external. This allows
	  automatically logging in when SSL client certificate is present.
	- *-login: Statistics were disabled if stats process connection was lost.
	- auth: Authentication master user login fails with SCRAM-* SASL mechanisms.
	- auth: With auth_cache_verify_password_with_worker=yes, passdb extra
	  fields in the auth cache got lost.
	- doveadm: Fixed crash if zlib_save_level setting was specified,
	  but zlib_save was unset. v2.3.15 regression.
	- doveadm: Proxying can panic when flushing print output. v2.3.17
	  regression. Fixes:
	  Panic: file ioloop.c: line 865 (io_loop_destroy): assertion failed:
	  (ioloop == current_ioloop)
	- doveadm: stats add --group-by parameter didn't work.
	- fts: Using email-address fts tokenizer could result in excessive memory
	  usage with garbage email input. This could cause the indexer-worker
	  processes to fail due to reaching the VSZ memory size limit.
	  Only applies when using libfts.
	- imap: A SEARCH command timing out while fts returns indexes may timeout
	  returning "NO [SERVERBUG]", while it should return "NO [INUSE]" instead.
	- imap: LIST-EXTENDED doesn't return STATUS for all folders. Sending
	  LIST .. RETURN (SUBSCRIBED STATUS (...)) did not return STATUS for
	  folders that are not subscribed when they have a child folder that is
	  subscribed as mandated by IMAP RFCs.
	- imapc: Mailbox vsize calculation crashed with
	  Panic: file index-mailbox-size.c: line 344 (index_mailbox_vsize_hdr_add_missing):
	  assertion failed: (mails_left > 0)
	- indexer: If indexer-worker crashes, the request it was processing gets
	  stuck in the indexer process. This stops indexing for the folder until
	  indexer process is restarted. v2.3.14 regression.
	- indexer: Process was slowly leaking memory for each indexing request.
	- lib-event: Unnamed events were wrongly filtered out for event/metric
	  filters like "event=abc OR something_independent_of_event_name".
	- lib-index: 64-bit big endian CPUs handle last_used field in
	  dovecot.index.cache wrong.
	- lib-ssl-iostream: Fix buggy OpenSSL error handling without assert-crashing.
	  If there is no error available, log it as an error instead of crashing.
	  The previous fix for this in v2.3.11 was incomplete. Fixes
	  Panic: file istream-openssl.c: line 51 (i_stream_ssl_read_real):
	  assertion failed: (errno != 0)
	- lmtp: Out-of-memory issues can happen when proxying large messages to
	  LMTP backend servers that accept the message data too slow.
	- master: HAProxy header parsing has read buffer overflow if provided
	  header size is invalid. This happens only if inet_listener
	  { haproxy=yes } is configured and only if the remote IP address is in
	  haproxy_trusted_networks.
	- old_stats: Plugin kept increasing memory usage, which became
	  noticeable with long-running imap sessions.
	- stats: Dynamically adding same metric multiple times causes multiple stats.
	- submission-login: Authentication does not accept OAUTH2 token (or
	  other very long credentials) because it considers the line to be too long.
	- submission-login: Process can crash if HELO is pipelined with an
	  invalid domain.
	- submission-proxy: Don't use SASL-IR if it would make the AUTH command
	  line longer than 512 bytes.
	- submission: Service would crash if relay server authentication failed.
	- virtual: FTS search in a virtual folder could crash if there are
	  duplicate mailbox GUIDs. This mainly happened when user had both INBOX
	  and INBOX/INBOX folders and the namespace prefix was INBOX/. Fixes
	  Panic: file hash.c: line 252 (hash_table_insert_node):
	  assertion failed: (opcode == HASH_TABLE_OP_UPDATE)
	- virtual: If mailbox opening fails, the backend mailbox is leaked and
	  process crashes when client disconnects. Fixes
	  Panic: file mail-user.c: line 232 (mail_user_deinit):
	  assertion failed: ((*user)->refcount == 1)
	- virtual: Searching headers in virtual folders didn't always use
	  full-text search indexes, if fts_enforced=no or body.

v2.3.17.1 2021-12-07  Aki Tuomi <aki.tuomi@open-xchange.com>

	- dsync: Add back accidentically removed parameters.
	- lib-ssl-iostream: Fix assert-crash when OpenSSL returned syscall error
	  without errno.
	- master: Dovecot failed to start if ssl_ca was too large.

v2.3.17 2021-10-28  Aki Tuomi <aki.tuomi@open-xchange.com>

	* 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.

v2.3.16 2021-08-06  Timo Sirainen <timo.sirainen@open-xchange.com>

	* Any unexpected exit() will now result in a core dump. This can
	  especially help notice problems when a Lua script causes exit(0).
	* auth-worker process is now restarted when the number of auth
	  requests reaches service auth-worker { service_count }. The default
	  is still unlimited.

	+ Event improvements: Added data_stack_grow event and http-client
	  category. See https://doc.dovecot.org/admin_manual/list_of_events/
	+ oauth2: Support RFC 7628 openid-configuration element. This allows
	  clients to support OAUTH2 for any server, not just a few hardcoded
	  servers like they do now. See openid_configuration_url setting in
	  dovecot-oauth2.conf.ext.
	+ mysql: Single statements are no longer enclosed with BEGIN/COMMIT.
	+ dovecot-sysreport --core supports multiple core files now and does
	  not require specifying the binary path.
	+ imapc: When imap_acl plugin is loaded and imapc_features=acl is used,
	  IMAP ACL commands are proxied to the remote server. See
	  https://doc.dovecot.org/configuration_manual/mail_location/imapc/
	+ dict-sql now supports the "UPSERT" syntax for SQLite and PostgreSQL.
	+ imap: If IMAP client disconnects during a COPY command, the copying
	  is aborted, and changes are reverted. This may help to avoid many
	  email duplicates if client disconnects during COPY and retries it
	  after reconnecting.
	- master process was using 100% CPU if service attempted to create more
	  processes due to process_min_avail, but process_limit was already
	  reached. v2.3.15 regression.
	- Using attachment detection flags wrongly logged unnecessary "Failed
	  to add attachment keywords" errors. v2.3.13 regression.
	- IMAP QRESYNC: Expunging UID 1 mail resulted in broken VANISHED
	  response, which could have confused IMAP clients. v2.3.13 regression.
	- imap: STORE didn't send untagged replies for \Seen changes for
	  (shared) mailboxes using INDEXPVT. v2.3.10 regression.
	- rawlog_dir setting would not log input that was pipelined after
	  authentication command.
	- Fixed potential infinite looping with autoexpunging.
	- Log event exporter: Truncate long fields to 1000 bytes
	- LAYOUT=index: ACL inheritance didn't work when creating mailboxes
	- Event filters: Unquoted '?' wildcard caused a crash at startup
	- fs-metawrap: Fix to handling zero sized files
	- imap-hibernate: Fixed potential crash at deinit.
	- acl: dovecot-acl-list files were written for acl_ignore_namespaces
	- program-client (used by Sieve extprograms, director_flush_socket)
	  may have missed status response from UNIX and network sockets,
	  resulting in unexpected failures.

v2.3.15 2021-06-21  Aki Tuomi <aki.tuomi@open-xchange.com>

	* CVE-2021-29157: Dovecot does not correctly escape kid and azp fields in
	  JWT tokens. This may be used to supply attacker controlled keys to
	  validate tokens, if attacker has local access.
	* CVE-2021-33515: On-path attacker could have injected plaintext commands
	  before STARTTLS negotiation that would be executed after STARTTLS
	  finished with the client.
	* Disconnection log messages are now more standardized across services.
	  They also always now start with "Disconnected" prefix.
	* Dovecot now depends on libsystemd for systemd integration.
	* Removed support for Lua 5.2. Use version 5.1 or 5.3 instead.
	* config: Some settings are now marked as "hidden". It's discouraged to
	  change these settings. They will no longer be visible in doveconf
	  output, except if they have been changed or if doveconf -s parameter
	  is used. See https://doc.dovecot.org/settings/advanced/ for details.
	* imap-compress: Compression level is now algorithm specific.
	  See https://doc.dovecot.org/settings/plugin/compress-plugin/
	* indexer-worker: Convert "Indexed" info logs to an event named
	  "indexer_worker_indexing_finished". See
	  https://doc.dovecot.org/admin_manual/list_of_events/#indexer-worker-indexing-finished
	+ Add TSLv1.3 support to min_protocols.
	+ Allow configuring ssl_cipher_suites. (for TLSv1.3+)
	+ acl: Add acl_ignore_namespace setting which allows to entirely ignore
	  ACLs for the listed namespaces.
	+ imap: Support official RFC8970 preview/snippet syntax. Old methods of
	  retrieving preview information via IMAP commands ("SNIPPET and PREVIEW
	  with explicit algorithm selection") have been deprecated.
	+ imapc: Support INDEXPVT for imapc storage to enable private
	  message flags for cluster wide shared mailboxes.
	+ lib-storage: Add new events: mail_opened, mail_expunge_requested,
	  mail_expunged, mail_cache_lookup_finished. See
	  https://doc.dovecot.org/admin_manual/list_of_events/#mail
	+ zlib, imap-compression, fs-compress: Support compression levels that
	  the algorithm supports. Before, we would allow hardcoded value between
	  1 to 9 and would default to 6. Now we allow using per-algorithm value
	  range and default to whatever default the algorithm specifies.
	- *-login: Commands pipelined together with and just after the authenticate
	  command cause these commands to be executed twice. This applies to all
	  protocols that involve user login, which currently comprises of imap,
	  pop3, submisision and managesieve.
	- *-login: Processes are supposed to disconnect the oldest non-logged in
	  connection when process_limit was reached. This didn't actually happen
	  with the default "high-security mode" (with service_count=1) where each
	  connection is handled by a separate process.
	- *-login: When login process reaches client/process limits, oldest
	  client connections are disconnected. If one of these was still doing
	  anvil lookup, this caused a crash. This could happen only if the login
	  process limits were very low or if the server was overloaded.
	- Fixed building with link time optimizations (-flto).
	- auth: Userdb iteration with passwd driver does not always return all
	  users with some nss drivers.
	- dsync: Shared INBOX not synced when "mail_shared_explicit_inbox" was
	  disabled. If a user has a shared mailbox which is another user's INBOX,
	  dsync didn't include the mailbox in syncing unless explicit naming is
	  enabled with "mail_shared_explicit_inbox" set to "yes".
	- dsync: Shared namespaces were not synced with "-n" flag.
	- dsync: Syncing shared INBOX failed if mail_attribute_dict was not set.
	  If a user has a shared mailbox that is another user's INBOX, dsync
	  failed to export the mailbox if mail attributes are disabled.
	- fts-solr, fts-tika: Using both Solr FTS and Tika may have caused HTTP
	  requests to assert-crash: Panic: file http-client-request.c: line 1232
	  (http_client_request_send_more): assertion failed: (req->payload_input != NULL)
	- fts-tika: 5xx errors returned by Tika server as indexing failures.
	  However, Tika can return 5xx for some attachments every time.
	  So the 5xx error should be retried once, but treated as success if it
	  happens on the retry as well. v2.3 regression.
	- fts-tika: v2.3.11 regression: Indexing messages with fts-tika may have
	  resulted in Panic: file message-parser.c: line 802 (message_parser_deinit_from_parts):
	  assertion failed: (ctx->nested_parts_count == 0 || i_stream_have_bytes_left(ctx->input))
	- imap: SETMETADATA could not be used to unset metadata values.
	  Instead NIL was handled as a "NIL" string. v2.3.14 regression.
	- imap: IMAP BINARY FETCH crashes at least on empty base64 body:
	  Panic: file index-mail-binary.c: line 358 (blocks_count_lines):
	  assertion failed: (block_count == 0 || block_idx+1 == block_count)
	- imap: If IMAP client using the NOTIFY command was disconnected while
	  sending FETCH notifications to the client, imap could crash with
	  Panic: Trying to close mailbox INBOX with open transactions.
	- imap: Using IMAP COMPRESS extension can cause IMAP connection to hang
	  when IMAP commands are >8 kB long.
	- imapc: If remote server sent BYE but didn't immediately disconnect, it
	  could cause infinite busy-loop.
	- lib-index: Corrupted cache record size in dovecot.index.cache file
	  could have caused a crash (segfault) when accessing it.
	- lib-oauth2: JWT token time validation now works correctly with
	  32-bit systems.
	- lib-ssl-iostream: Checking hostnames against an SSL certificate was
	  case-sensitive.
	- lib-storage: Corrupted mime.parts in dovecot.index.cache may have
	  resulted in Panic: file imap-bodystructure.c: line 206 (part_write_body):
	  assertion failed: (text == ((part->flags & MESSAGE_PART_FLAG_TEXT) != 0))
	- lib-storage: Index rebuilding (e.g. via doveadm force-resync) didn't
	  preserve the "hdr-pop3-uidl" header. Because of this, the next pop3
	  session could have accessed all of the emails' metadata to read their
	  POP3 UIDL (opening dbox files).
	- listescape: When using the listescape plugin and a shared namespace
	  the plugin didn't work properly anymore resulting in errors like:
	  "Invalid mailbox name: Name must not have '/' character."
	- lmtp: Connection crashes if connection gets disconnected due to
	  multiple bad commands and the last bad command is BDAT.
	- lmtp: The Dovecot-specific LMTP parameter XRCPTFORWARD was blindly
	  forwarded by LMTP proxy without checking that the backend has support.
	  This caused a command parameter error from the backend if it was
	  running an older Dovecot release. This could only occur in more complex
	  setups where the message was proxied twice; when the proxy generated
	  the XRCPTFORWARD parameter itself the problem did not occur, so this
	  only happened when it was forwarded.
	- lmtp: The LMTP proxy crashes with a panic when the remote server
	  replies with an error while the mail is still being forwarded through
