[0.16.17] - 2026-08-10

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• IMAP:
  • UIDBATCHES extension (RFC 10022).
  • UIDONLY extension (RFC 9586).
  • MESSAGELIMIT and SAVELIMIT extensions (RFC 9738).
• WebDAV: Range and If-Range header support on file downloads (RFC 7233) (#2377).
• Spam filter: url_original expression variable for Url rules.

Changed

• Memory allocator: Replaced the unmaintained jemallocator crate with tikv-jemallocator (contributed by @checkraisefold).
• ACME registry: Use description as label property.

Fixed

• MTA:
  • Certificates for domains publishing an enforcing MTA-STS policy are always validated, even in the fallback TLS strategy.
  • DSN delivery date uses wrong timestamp.
  • FUTURERELEASE HOLDUNTIL uses Unix timestamps instead of RFC 3339 date-times.
• JMAP:
  • EmailSubmission/query filtering on undoStatus contradicts EmailSubmission/get, reporting held FUTURERELEASE submissions as final instead of pending.
  • EmailSubmission/get requests without an ids argument iterates the wrong index.
• CardDAV: Accept: text/vcard version negotiation is ignored whenever another parameter such as q or charset follows version=.
• Calendar: Server-side scheduling messages place the text/calendar part outside the multipart/alternative and disposed as an attachment.
• Sharing: Accounts holding the impersonate permission never have their ACL grants collected, so shared items are never listed in JMAP sessions, CalDAV/CardDAV discovery or IMAP.
• IMAP:
  • COPY/MOVE into a shared folder fails with NO [ALREADYEXISTS] when the destination account already holds the message, leaving the message in the source mailbox and clients in a retry loop.
  • BODYSTRUCTURE and ENVELOPE return MIME parameters, Content-Description, subjects and display names as raw UTF-8 even to sessions that never enabled UTF8=ACCEPT.

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[0.16.16] - 2026-08-02

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• JMAP Email Delivery Push Notifications (draft-ietf-jmap-emailpush-03)
• MTA: Allow System Sieve scripts to access orcpt during the DATA stage.

Changed

• S3: accessKey can now be read from an environment variable or file.

Fixed

• Meilisearch: Verify index existence using GET instead of creating a new task which times out on busy servers.
• Branding: Stalwart logo flashes before the per-tenant logo is loaded on the login page.
• Calendar: iMIP and alarm notification messages embed the default logo using bare LF line endings, producing a single 4247 octet line that strict SMTP relays reject with line too long.
• DMARC: Failure reports state Identity-Alignment: none when a mechanism authenticated successfully but against an identity that is not aligned with the From domain.
• Redis: Task and queue locks are never released after a worker dies, because failed lock attempts refresh the lock expiry.
• Recovery mode: Download WebUI if missing.
• Logging: The systemd journal tracer omits the parent span's fields.
• MTA:
  • BDAT chunks sent without a valid MAIL FROM are answered with 552 5.3.4 Message too big for system instead of 503 5.5.1.
  • A maxMessageSize of 0 rejects every message with 552 5.3.4 Message too big for system instead of disabling the size limit.
• Windows: Listeners bound to the unspecified IPv6 address ([::]), including all defaults, refuse IPv4 connections such as 127.0.0.1, since IPV6_V6ONLY is enabled by default on Windows.

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[0.16.15] - 2026-07-26

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

Changed

Fixed

• JMAP:
  • Email/copy should return alreadyExists when copying a message to a mailbox that already contains it.
  • Email/copy with onSuccessDestroyOriginal destroys the copy's creation id instead of the source Email id.
  • CalendarEvent/set does not generate a uid on create when the client omits it.
  • CalendarEvent/set does not refresh the updated property (iCalendar DTSTAMP) on create or update.
  • EmailSubmission/set rejects valid recipients whose domain is itself a public suffix (e.g. gov.in, co.uk).
  • Requests are rejected with notRequest when a method name contains a JSON-escaped solidus (e.g. Core\/echo).
• MTA: Panic when MTA-STS is disabled and a remote MTA fetched /.well-known/mta-sts.txt.
• Auth: Scoped credentials with SysApiKeyCreate or SysApiKeyUpdate permissions can regain its own account's full rights.
• Web Push: Valid VAPID keys are rejected when PEM-encoded with explicit EC parameters, in SEC1 (EC PRIVATE KEY) format, or with a leading byte-order mark.
• Encryption at rest: Appended messages are encrypted for accounts that did not opt in to encryptOnAppend.
• Cache: Account caches silently discard entries larger than a single quick-cache shard, causing constant database rebuilds.
• Registry: Id references (e.g. #certificate-...) fail to resolve on defaultCertificateId, defaultAdminRoleIds, listenerIds and publicKey.
• Search: reindex drops calendar and contact index tasks for accounts with fewer than a full batch of items.
• Migration: Abort --import when the target already contains data in the key range being imported.
• Cluster: Broadcast subscriber re-subscribes after every message, losing bursts of cluster broadcasts during the reconnect window.
• Enterprise: Per-tenant logo is not shown on the OAuth login password and OTP screens, which are served from the server's canonical host rather than the tenant domain.

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[0.16.14] - 2026-07-20

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• Use of Voluntary Application Server Identification (VAPID) in JMAP Web Push (RFC 9749).

Changed

Fixed

• IMAP:
  • Mailbox object-quota only enforced in JMAP.
  • Pipelined STORE and EXPUNGE can execute out of order.
• JMAP:
  • Read-only sharee cannot set isSubscribed on a shared mailbox.
  • Web Push payloads with Content-Encoding: aes128gcm should not be base64-encoded but sent as raw bytes.
  • Stale push subscription can block verification of a new one.
  • PushSubscription/set rejects the unpadded base64url keys the W3C Push API produces.
  • Email/import does not send push notifications for imported messages.
  • CalendarEvent/set silently ignores ifInState.
• CalDAV: calendar-query REPORT returns empty calendar-data for JMAP-created events.
• MTA:
  • DMARC is skipped when MAIL FROM SPF is unavailable.
  • queue_name variable not available in rate limiter expressions.
• Calendar:
  • No expanded occurrences are returned for a daily recurrences crossing DST.
  • Uppercase MAILTO calendar addresses become invalid SMTP recipients.
  • Scheduling invitations on a shared, non-owned calendar fail with MAIL FROM unauthorized.
• HTTP: Disable allowedEndpoints expression in recovery mode.
• Telemetry: Tasks are serialized to the wrong store when using separate stores for telemetry and data.

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[0.16.13] - 2026-07-12

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Added

• FreeBSD support.

Changed

Fixed

• OAuth resource indicators: Accept imap, smtp, pop3 and sieve as valid resource indicators for OAuth access tokens.
• PostgreSQL: Incomplete channel binding implementation.
• JMAP:
  • VacationResponse: isEnabled reset to false whenever properties are changed.
  • Capabilities: Return RFC-3339-conformant UTCDate literals in capabilities: min 0001-01-01T00:00:00Z, max 9999-12-31T23:59:59Z.
• Directory: Update local groups only when the external directory includes a group attribute.
• DNS Management:
  • CAA management deletes too third-party CAA entries.
  • Multiple provider fixes (see dns-update crate changelog).
• Reject invalid duration values (e.g. 1h30m).
• Branding: Custom logos for domains do not work.
• Sieve: add Received headers to auto-generated messages and detect loops.
• MTA: Resume queue processing does not work.
• Misconfigured in-memory store cannot be recovered in recovery mode.

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[0.16.12] - 2026-07-06

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• DKIM2 implementation (draft-ietf-dkim-dkim2-spec-03).
• DMARCbis implementation:
  • Domain-based Message Authentication, Reporting, and Conformance (DMARC) (RFC 9989)
  • DMARC Aggregate Reporting (RFC 9990)
  • DMARC Failure Reporting (RFC 9991)

Changed

Fixed

• DANE: Treat DNSSEC bogus as a temporary failures to prevent downgrade attacks.
• OIDC provider:
  • ECDSA private key support for SEC1 format.
  • Allow ports in redirect_uri for loopback addresses.
• OIDC directory:
  • Removing a user from all groups does not sync the changes correctly.
  • Fetch name and group claims from userinfo endpoint when missing from the JWT token.
• PostgreSQL: Include error chain in error messages.
• Prometheus: event counters are exported with incorrect metric names.
• Registry: Changing the type of an existing account from user to group panics.
• Masked emails: Return UnknownRecipient only for disabled or expired masked emails.
• IDN: sanitize_email rejects valid Punycode domains.
• Auto-ban: IP block expiration ignores per-reason ban durations.
• Meilisearch: Limit the text search scope using attributesToSearchOn.
• CalDAV: calendar-query REPORT returns invalid HTTP 404 when no events match the query.
• Snowflake past id generation fails when the provided duration is longer than 4 years.
• Calendar scheduling: Wrong RSVP base URL is used.
• Network listener: Accept loop spins all CPU cores with no back-off when the process hits EMFILE (too many open files).
• Cluster: Broadcast MTA queue refresh events to all nodes.

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[0.16.11] - 2026-06-25

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• Encryption-at-rest: Support for AES-256-GCM and ChaCha20-Poly1305 for S/MIME (#161).
• S3: Support for allowInvalidCerts option to allow connecting to S3 endpoints with invalid TLS certificates.
• Redis Sentinel support as an in-memory store and cluster coordinator backend (#2430).

Changed

Fixed

• DANE: Verify DNSSEC is supported by the resolver before attempting to validate TLSA records.
• TLS: Update search index when file-backed certificates are refreshed.
• JMAP: Principal/query returns broad results when a name or email filter cannot be resolved.
• Webhooks: event IDs collide for same event type emitted in the same second.

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[0.16.10] - 2026-06-21

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• International Domain Names (IDN) support (#207).
• OAuth:
  • OAuth Profile for Open Public Clients (draft-ietf-mailmaint-oauth-public)
  • Client secret verification for confidential clients.
• HTTP: Add redirectRoot option to Http object to allow redirecting requests to the root path to a different path (e.g. /account).
• ACME: reuseKey option to allow reusing private keys in renewals.
• IMAP:
  • IMAP Extension for Object Identifiers (draft-ietf-mailmaint-imap-objectid-bis)
  • GETJMAPACCESS command to discover the JMAP session resource URL (#2736).

Changed

Fixed

• JMAP conformance (pass the jmap-test-suite tests):
  • Methods are only available if their capability is in using.
  • Reject requests that do not specify application/json in the Content-Type header.
  • Require accountId argument on requests.
  • Return unparsable ids in notFound / notUpdated / notDestroyed / notCopied instead of dropping them.
  • Default calendars and address books are not subscribed by default.
  • */set: Unchanged immutable id property is rejected on update.
  • */query and */queryChanges: nullrejected asnotRequest`.
  • Email/query:
    • Improper anchor handling.
    • Total miscount when collapseThreads is enabled.
    • Wrong sort order on hasKeyword, allInThreadHaveKeyword, and someInThreadHaveKeyword conditions.
    • Non-standard header values are not searchable.
  • Email/copy: Take the source message id from the value's id property.
  • Email/set: Bump reference-resolution max_depth from 1 to 2.
  • Email/import: Reject blobs that do not contain valid messages.
  • EmailSubmission/set: return sendAt and undoStatus in the created response.
  • Mailbox/set: Return alreadyExists instead of invalidProperties when creating a mailbox with an existing name.
  • SearchSnippet/get: incorrect response structure.
  • Thread/changes: emit a container delete when a thread becomes empty.
  • VacationResponse/set: incorrect singleton handling.
• IMAP: Discard oversized non-synchronizing literals (#2768).
• DANE: Improper TLSA record validation (#2328 - credits to @vdukhovni).
• OIDC: Add default domain name to groups that are not email addresses.
• RocksDB: Enable blob garbage collection to reclaim disk space from deleted blobs.
• Sieve: include statements ignore capitalisation of sub-script names (#1643)
• Cache: Invalidate negative email caches when an account is created.
• Troubleshoot tool: Use the configured source IP address when connecting to remote servers (#2867).

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[0.16.9] - 2026-06-15

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• ACME: Allow specifying a preferred certificate chain.

Changed

Fixed

• JMAP: */changes methods leak ids of non-shared objects (reported by @5ud0er).
• Sieve: Do not allow invalid certs in http_header function.
• FoundationDB: Fix read version cache expiration logic.
• MTA: Re-scheduling or editing a queued message reports success but persists nothing for recipients in a non-default virtual queue.
• CardDAV: Version requests included in address-data are ignored.
• ACME: Add freshness check when renewing certificates.
• Autodiscover v2: Read email address from query parameters.
• Sieve: Do not keep copies of redirected messages when keep is not specified.
• Registry: Object ids are parsed as numbers.

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[0.16.8] - 2026-06-06

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

Changed

• OAuth: Rework access tokens to an AES-256-GCM-SIV AEAD format that carries the account name for proxy routing.
• Added more internal TLDs to the domain validation.

Fixed

• MTA:
  • Sub-addressing with external directories returns 550 Mailbox not found.
  • Disabled aliases continue receiving messages.
• JMAP for File Storage: FileNode/get returns a stale state string.
• Make SieveSystemInterpreter.defaultReturnPath and MtaQueueQuota.match optional expressions.
• Rate limiter panics when periods under 1 second are used.
• CalDAV/CardDAV: Calendar events, contacts, calendars and address books deleted via JMAP do not write a vanished tombstone.
• DNS updater: bump to dns-update-v0.5.1.

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[0.16.7] - 2026-05-28

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• RateLimit header fields for HTTP (draft-ietf-httpapi-ratelimit-headers-10)
• MTA: Implement spamtest in trusted Sieve scripts.

Changed

Fixed

• Log rejected messages to tracing store.
• MTA:
  • Always update next DSN notify times.
  • Expand lists and resolve catch-all addresses when building autogenerated messages.
• Sharing: Includes resource that themselves carry a direct ACL grant and are leaves.
• Tasks cannot be deleted in OSS builds.
• Directory: Per-domain external directory resolution fails.
• DNS updater: Keep external TXT records when updating RRSet.
• HTTP: Reject requests from blocked IPs when Keep-Alive is enabled.

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[0.16.6] - 2026-05-20

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• Added 58 new DNS provider integrations (see dns-update crate for details).
• DNS updater: Log DNS record types and values.
• Sieve: Allow User Sieve scripts to access orcpt.
• MTA: Log when messages are rejected or discarded by the spam classifier.

Changed

• Bump JMAP File Storage to draft-ietf-jmap-filenode-14.
• Accept password hashes with $ or { prefixes as secure secrets.

Fixed

• DAV: acl-principal-prop-set REPORT enforced the wrong privilege.
• JMAP: Thread/get did not filter by per-mailbox ACLs on shared accounts.
• IMAP: UID FETCH N:* could miss messages moved into a SELECTed mailbox by another connection.
• DNS updater:
  • Skip v=spf1 a -all records for apex domains.
  • RFC2136 TSIG: regression related to multiplexer.
  • Route53: Chunk TXT records when they exceed 255 characters.
• ACME:
  • Update defaultCertificateId when renewing a certificate that is currently set as default.
  • Perform DNS-01 authorizations sequentially to avoid race conditions in some DNS providers.
• Allow internal TLDs and special characters in e-mail addresses.
• Websocket: Perform case insensitive matching during upgrade.
• LDAP: Synchronize accounts when expanding mailing list recipients.
• Sieve: replace action adds an extra From header.
• ACL: Orphaned ACL entries for deleted accounts cause JMAP session errors.

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[0.16.5] - 2026-05-11

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• is_ip_in_cidr expression function for CIDR matching.

Changed

• Bump mail-auth to 0.9 (which bumps hickory-resolver to 0.26).
• Deprecated RFC2136 SIG(0) support as it is no longer supported by hickory.

Fixed

• JMAP:
  • Patching ids containing digits in JSON Pointers fails.
  • Patching nested objects with null values fails.
• External directories:
  • SQL: Return Failed instead of Error when the query returns no results.
  • LDAP: Impersonation fails when the user has not logged in before.
• Network: Attempt binding to IPv4 when binding to IPv6 fails with EAFNOSUPPORT error.
• Bootstrap: Timeout after 30 seconds when probing the data store.
• HTTP: Use permissive CORS headers for .well-known endpoints.
• ACME:
  • Include apex domains when requesting certificates for subdomains.
  • Use the public suffix list to determine the zone name when no origin is provided.
• MTA:
  • Allow rescheduling recipients with permanent failures.
  • Process reports using original RCPT before rewriting.
• Autodiscover v2 endpoint unreachable.
• DNS update (via dns-update crate):
  • OVH + Google Cloud DNS: Fix FQDN handling for MX and SRV records.
  • Route53: Fix changeset error resolution.
  • deSEC: Use empty subname for apex records instead of @, which the API rejects.
  • Cloudflare: Wrap TXT record content in double quotes (RFC 1035) to suppress dashboard warnings.
• iCalendar/JSCalendar (via calcard crate):
  • Support STATUS:CANCELLED mapping from VTODO to JSCalendar.
  • Fixed duration parsing for zero duration PT0S.

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[0.16.4] - 2026-05-05

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

Changed

Fixed

• Live tracing in community and OSS versions.
• Timezone changes from the AccountSettings object return invalidProperties.
• mail-parser panic with certain messages containing corrupted attachments.
• Pagination by anchor for queued messages, tasks and metrics.
• Spam filter: Use original instead of rewritten RCPT on checks.
• JMAP:
  • References in nested objects not resolved.
  • AddressBook/query fetches wrong resources.
• Import tool fails to restore registry entries.
• FDB: Allow multiple FoundationDB instances in the same process.
• Autoconfig: Return %EMAILADDRESS% when no email address is provided.
• Quota: Include Sieve scripts in quota recalculations.

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[0.16.3] - 2026-04-30

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

Changed

• Replaced STALWART_HTTPS_PORT with STALWART_PUBLIC_URL.
• App Passwords now begin with app_ instead of app to avoid issues with some clients that do not support spaces in passwords.

Fixed

• Directory:
  • Invalidate caches when group memberships change on an external directory.
  • OIDC: errors instead of "failed to decode token".
  • OIDC: Recovery admin access.
  • User impersonation.
• Tasks:
  • Delete locked tasks.
  • Queue pagination by anchor.
• Log viewer: All events show as INFO.
• Registry: Allow changing object variants.
• Node id renewal.
• DNS Updater: Fix Route53 serialization format.

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[0.16.2] - 2026-04-28

If you are upgrading from v0.16.x, replace the binary (or run docker pull). If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• OIDC: Fallback to userinfo endpoint when JWT token does not contain an email claim.
• S3: verifyAfterWrite option to verify that objects have persisted after writing.

Changed

• Allow HTTP to be used for configuring the server.

Fixed

• LDAP: Generate valid credentialId when there are password changes.
• TLS: Disable cipher suited option disables wrong ciphers.
• DNS Updater:
  • BunnyDNS: Use subdomain as name of record instead of FQDN.
  • RFC2136: Chunk TXT records.
• Skip invalid entries in log files.

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[0.16.1] - 2026-04-25

This version includes multiple breaking changes. If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• OIDC: Extract username from JWT token.
• system('node_hostname') and system('node_role') expression variables to retrieve the local node hostname and cluster role respectively.

Changed

Fixed

• JMAP:
  • Invalid receivedAt headers after importing (#2939).
  • Sorting order issues when emails lack receivedAt headers.
• IMAP: Fix BINARY fetch responses (#2940).
• WebDAV: Fix ACL validation for target folders.
• ACME: Allow requesting apex domain certificates.
• Hostname issues:
  • Accept RFC 6761 reserved TLDs during bootstrap.
  • Allow hostnames without TLDs in remote server settings.
• Reverse proxy issues.
• OSS builds.
• DNS Updater:
  • RFC2136: TSIG secret not base64 decoded.
  • Google DNS: Chunk TXT records when they exceed 255 characters.
  • Cloudflare:
    • Fix CAA record updates.
    • Check zone subdomains when finding zones

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[0.16.0] - 2026-04-20

This version includes multiple breaking changes. If you are upgrading from v0.15.x and below, please read the upgrading documentation for more information on how to upgrade from previous versions.

Added

• Web UI rewritten from the ground up using the JMAP management API, featuring a refreshed design and addressing 76 enhancement requests and bug fixes.
• CLI rewritten from the ground up to use the JMAP management API.
• Security enhancements:
  • Password strength enforcement using the zxcvbn algorithm
  • Password expiration, rotation policies and IP address restrictions for user accounts
  • App Passwords with limited access (#1609), labels (#2255), IP address restrictions and expiration dates
  • API keys with limited access, labels, IP address restrictions and expiration dates
  • Auto-ban comments and details about the triggering event (#1321)
  • Auto-ban expiration after a configurable time period (#964)
• DNS Management:
  • Automatic DNS management of MX, TXT, CNAME, SRV, CAA and TLSA records (#463 #1017 #1419 #2438 #1370 #1406 #1371)
  • Automatic update of TLSA records when ACME certificates change (#1664)
  • RFC2136 SIG(0) support (#856)
  • Route53 provider support (contributed by @jimmystewpot)
  • Google Cloud DNS provider support (contributed by @jimmystewpot)
  • Bunny provider support (contributed by @angeloanan)
  • Porkbun provider support (contributed by @jeffesquivels)
  • DNSimple provider support (contributed by @NelsonVides)
  • Spaceship provider support (contributed by @matserix)
• DKIM:
  • Automatic DKIM key generation, rotation and DNS management (#368 #961)
  • Store DKIM keys in the database (#1264)
  • Ignore insecure signatures when verifying DKIM (#1068 #467)
• ACME/TLS:
  • DNS-PERSIST-01 ACME challenge support (#2837)
  • Renew certificates on demand, view certificate details (#675 #1162 #2566)
  • CAA record support (#468) with accounturi parameter (#1933)
  • TLSA records publishing restricted to 3 1 1 and 2 1 1 (#2193)
• OIDC and OAuth:
  • JWT token validation without requesting userinfo from the OIDC provider.
  • Audience (aud) claim (#2603) and scope validation support.
  • Groups support (#1448)
  • RFC 7636 - Proof Key for Code Exchange by OAuth Public Clients
• LDAP:
  • Separate filter for groups (#1841)
  • Improve support for OpenLDAP schemas (#760)
  • Improve and simplify LDAP settings (#2194 #2174)
• Directory:
  • Masked email addresses for enhanced privacy (Enterprise)
  • Domain aliases (#583)
  • E-mail alias descriptions and option to disable aliases (#506)
  • Account archiving and un-deletion (#2767) (Enterprise)
  • Per-domain directory backends (Enterprise)
• Account configuration and discovery:
  • Automatic Configuration of Email, Calendar, and Contact Server Settings (draft-mailmaint-uaautoconf-04) (#2201)
  • MS Autodiscover V2 support (#679)
• Sieve: Allow deactivating scripts without deleting them (#1251).
• Tracing: Enable events only mode (#2276)
• Clustering:
  • Automatic cluster node ID generation and management.
  • Unified cluster management (#960)
  • Outbound MTA role (#1692)

Changed

• Replaced REST API with JMAP API (#2262 #959 #1480)
• Removed support for Authenticated Received Chain (ARC) sealing (learn more).
• Directory: Removed smtp, imap and memory directory backends.
• Use aws-lc for cryptographic operations instead of ring.
• Use rustls-platform-verifier for TLS certificate verification instead of webpki (#247).

Fixed

• Directory:
  • Cannot remove built-in "admin" role from user once it was assigned (#1467)
  • Delete associated records (#963)
  • Updated Role permissions not applied (#2038)
  • Recreated account cannot log in until server is restarted (#1469)
  • Subaddressing does not work for groups (#475)
  • New LDAP aliases are rejected (#1318).
  • Validate account and group names (#2209)
• MTA:
  • RCPT TO stage settings improvements (#2217 #394)
  • Relay to IP addresses (#838)
  • Duplicate delivery inverted check
  • SASL challenge responses include invalid Go ahead text
• JMAP:
  • Fix inMailboxOtherThan query logic.
  • Fix hasAttachment search field (#2778)
• IMAP:
  • Increment argument max length to 8000 bytes
  • ACL: Add RIGHTS capability (#2762)
  • ACL: Fix ACL SET permission override.
• WebDAV:
  • Return 304 NOT_MODIFIED on If-None-Match
  • Use RFC 2616 instead of RFC 1123 for date formatting
  • Fix ACL container/item mismatch in reports.
  • CalDAV: Allow organized properties to be present in PUT requests if they are equal to the existing ones.
  • CalDAV: Enforce cumulative iCalendar instances cap in CalDAV free-busy REPORT handler
• Configuration: Prefix parsing issues (#2495)
• OIDC: JWKS Exposes Symmetric Signing Key
• SQLite: Fix thread pool exhaustion.
• PostgreSQL: Use clean recycling method on connection pool
• Meilisearch: Make id sorteable.
• ACME: Fix wrong origin for subdomain updates (#2360)
• Spam filter: Skip invalid messages during training.
• Calendar: Include minutes in localized invite templates (#2828)
• HTTP: Fix 204 CORS preflight responses

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