v0.16.17

[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.

---

Check binary attestation here