After six months of development, DavMail, an open-source, Java-based cross-platform Exchange and Office 365 gateway that enables users to integrate their preferred email and calendar clients—such as Thunderbird—with Microsoft Exchange servers, has reached version 6.4.
One of the most notable changes is the introduction of an experimental Microsoft Graph backend. While still in progress, it lays the groundwork for broader support of Microsoft’s modern API, with improvements in calendar, contacts, and task handling.
Related updates include adjustments to OIDC authentication, additional scope handling, and better error reporting for Outlook and Office 365 accounts.
On the IMAP side, Davmail 6.4 addresses a long-standing issue with synchronizing shared mailboxes. It also adds support for iOS 18’s comma-separated UID search, refines the SPECIAL-USE implementation, and merges user contributions that simplify keepalive behavior.
For authentication, the release restores JCIFS NTLM support via a new “davmail.enableJcifs” setting. Improvements were also made to NTLM logging and message decoding, providing better debugging options.
Linux users will notice packaging adjustments, including the removal of the Eclipse SWT dependency on SUSE in favor of the included SWT package, new RPM spec fixes for RHEL 9, and upstreamed patches for Flatpak builds.
It is also worth noting that DavMail 6.4 fully migrates its logging framework from Log4j to Reload4j, updating related dependencies and removing outdated log viewers.
Other highlights include refinements in Office 365 token handling, improved error messages for password expiration, updates to Docker entrypoint scripts, and fixes for CalDAV parameter escaping.
For more information, see the announcement.
