The following was posted on the SpamSieve blog:

Version 2.9.29 of SpamSieve is now available. This is a free update that includes the following changes:

  • Works with Apple Mail under macOS 10.13 High Sierra (currently in beta). It’s easiest if you update to SpamSieve 2.9.29 before updating to 10.13. In any case, if you don’t see the SpamSieve commands in Apple Mail’s Message menu, be sure to choose Install Apple Mail Plug-In from the SpamSieve menu. Otherwise, with the SpamSieve plug-in not installed, Mail will move good messages to the spam mailbox without consulting SpamSieve.
  • To get the improvements (described below) to SpamSieve’s integration with Microsoft Outlook 2016, please follow these instructions after updating SpamSieve:

  • Made various changes to improve SpamSieve’s filtering accuracy.
  • Made various improvements to the Outlook - Filter Mailboxes app for Microsoft Outlook 2016:
    • The Setting Up Outlook 2016 section of the manual has been updated to be more complete and clear.
    • Worked around a hang in Outlook when there are lots of messages in the inbox.
    • There is an optional “Large Inboxes” setup that can greatly speed up the processing of new messages if you have lots of old messages in your inbox.
    • Filtering now works when the Mac is running in Dutch or Swedish.
    • It is now possible to configure the options using esoteric preferences links, so that you don’t have to edit the script itself.
    • Improved the debug logging and error reporting.

  • Worked around a bug in Microsoft Outlook 15.36 were it could incorrectly report that no messages were selected, thus preventing training from working.
  • The Apple Mail - Remote Training script now sets and clears message background colors and (optionally) flags. This way if a server filter and SpamSieve share the same Spam mailbox, you can easily see which messages are confirmed as spam by SpamSieve because they will be marked in its normal way.
  • Improved the following sections of the manual:

  • Improved the scrolling speed in the Blocklist, Corpus, and Whitelist windows.
  • The diagnostic reporter can now check whether the application package is damaged
  • SpamSieve is better at detecting and reporting problems with the launch agent.
  • Logged errors now use indentation to improve readability.
  • SpamSieve now fixes the permissions of the log file if it can’t append to it (and worked around an OS bug reporting such errors).
  • Improved the Apple Mail debug logging.
  • Improved the reporting of corpus reset errors.
  • Improved the error reporting for damaged files.
  • Documentation and Help menu links to c-command.com now use https instead of http.
  • Made various code modernizations.
  • Fixed a bug that could cause a -10004 error when filtering messages for Microsoft Outlook 2016.
  • Fixed a bug that could cause a crash when processing incoming Apple Mail messages on macOS 10.13.
  • Fixed a bug where some Preferences window labels were truncated on Mac OS X 10.10 due to OS font changes.

SpamSieve 2.9.29 works with macOS 10.6 through 10.13 and requires an e-mail client. Older versions are available for older operating systems. For information about previous releases of SpamSieve, please see the version history.