Hi,

One interesting thing in this release is the support for configuring OAUTH2 openid-configuration element. It would be nice if IMAP clients started supporting this feature to enable OAUTH2 for all IMAP servers, not just Gmail and a few others. This would allow all kinds of new authentication methods for IMAP and improve the authentication security in general.

https://dovecot.org/releases/2.3/dovecot-2.3.16.tar.gz
https://dovecot.org/releases/2.3/dovecot-2.3.16.tar.gz.sig

Binary packages in https://repo.dovecot.org/
Docker images in https://hub.docker.com/r/dovecot/dovecot

* 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.