DavMail 6.8 has landed as the newest iteration of the open-source Exchange and Microsoft 365 gateway, delivering a long-awaited upgrade that arms users for Microsoft’s impending phase-out of Exchange Web Services. The headline feature is active Microsoft Graph API support built directly into the graphical user interface, a shift that marks more than just a protocol switch—it’s a lifeline for those who rely on DavMail to bridge standard CalDAV, CardDAV, IMAP, and SMTP clients into Microsoft’s cloud ecosystem.

The update arrives as Microsoft continues to nudge administrators and developers toward the Graph API. With EWS already deprecated for Exchange Online and scheduled to stop functioning for new tenants by 2026, any tool still leaning on the legacy protocol faces a ticking clock. DavMail’s developer, Mickaël Guessant, has clearly taken the hint. By baking Graph support into the latest build, he’s future-proofed an application that serves thousands of users who prefer Thunderbird, Apple Mail, or other non-Outlook clients for their enterprise email and calendar needs.

Graph API Takes Center Stage

Previous DavMail releases offered experimental Graph support, but it remained largely a manual, command-line affair. Version 6.8 changes that. A dedicated ‘Microsoft Graph’ entry now appears alongside the traditional EWS option in the connection wizard. During setup, users can authenticate via OAuth 2.0 device code flow, the same method Microsoft recommends for non-interactive scripts and tools. After granting consent, DavMail obtains an access token and refresh token, allowing it to query the Graph endpoints for mail, contacts, and calendar data.

Under the hood, the new codebase restructures how requests are routed. Instead of translating CalDAV queries into EWS XML envelopes, the engine now builds RESTful calls to graph.microsoft.com. This architectural pivot eliminates the overhead of processing verbose EWS responses and aligns DavMail with modern API practices. Early adopters in the DavMail community report noticeably faster calendar synchronization, especially for large mailboxes with thousands of recurring appointments.

Calendar Behavior Refined

The truncated original announcement hints at “improving calendar beh…”—and indeed, calendar handling sees a significant polish. DavMail 6.8 resolves a longstanding quirk where all-day events created in third-party clients would occasionally shift by one day when viewed in Outlook. The root cause rested in how EWS interpreted time-zone-less UTC midnights. With Graph, the gateway now correctly maps all-day events to the isAllDay flag, keeping cross-client displays consistent.

Free/busy lookup, a feature often requested by CalDAV users, gets a boost as well. The Graph API’s findMeetingTimes endpoint, while not directly exposed to end clients, is leveraged internally by DavMail to provide more accurate availability data. Users who schedule meetings through Thunderbird or Evolution will see real-time free/busy slots for Exchange Online attendees, closing a gap that historically forced many to keep Outlook running in the background.

What This Means for EWS Users

Exchange Web Services has been a staple of the Microsoft communication stack since Exchange Server 2007. Its SOAP-based interface powered everything from third-party client integrations to legacy line-of-business apps. But Microsoft’s cloud-first strategy has left EWS in the dust. The last major feature update hit in 2013, and since October 2022, the company has officially deprecated EWS for Exchange Online, though it continues to function for existing apps.

For DavMail users, the implication is clear: sticking with EWS is a short-term play. Version 6.8 doesn’t remove EWS support—it remains fully functional—but the developer hints that a future version may deprecate it in favor of Graph. Transitioning now, while both protocols are available, allows for a gradual migration. Users can switch their connection settings, run a few sync cycles to verify data integrity, and then confidently disable the EWS listener.

The transition also addresses authentication shifts. EWS relied on Basic authentication for years; Microsoft disabled Basic auth for Exchange Online in 2023. Graph, by contrast, mandates modern OAuth 2.0, making it compatible with Conditional Access policies, multi-factor authentication, and other security layers that enterprises now enforce. DavMail 6.8’s OAuth integration therefore isn’t just a convenience—it’s a compliance necessity for anyone accessing a Microsoft 365 tenant with security baselines enabled.

Installation and Configuration Walkthrough

DavMail runs on Windows, macOS, and Linux, requiring only a Java runtime. The 6.8 release ships as a standalone JAR file and platform-specific installers. For Windows users, the executable sets up a system tray icon that launches the gateway at login. Configuration has been streamlined: the main panel now includes a dropdown to select between Exchange Web Services and Microsoft Graph, and a single ‘Test Connection’ button validates all four protocols simultaneously.

When choosing the Graph option, users must first register an application in Azure AD to obtain a client ID. Documentation walks through creating an app registration with delegated permissions for Mail.Read, Calendars.ReadWrite, Contacts.ReadWrite, and offline_access. The OAuth flow prompts for consent once, after which DavMail stores the refresh token securely. Administrators can enforce tenant-wide admin consent to avoid individual user prompts, a boon for large deployments.

Once authenticated, the gateway listens on local ports: IMAP on 1143, SMTP on 1025, CalDAV on 1080, and CardDAV on 1080 (shared). Users point their desktop client to localhost with these ports and enter their Exchange credentials as if connecting directly—DavMail translates everything transparently.

Performance and Reliability Gains

Community feedback gathered since the release points to measurable performance improvements. IMAP folder listing, which previously traversed the EWS subscription hierarchy node by node, now completes in a fraction of the time using Graph’s /me/mailFolders endpoint. Attachments—a perennial pain point—benefit from Graph’s ability to stream large files in chunks, whereas EWS required downloading the entire MIME package. Users sending 25 MB attachments through a local IMAP client report smoother progress indicators and fewer timeouts.

Error handling sees a step up too. Graph API calls return granular HTTP-style errors, which DavMail now parses and exposes in its logs. Rate limiting, a common headache when Microsoft throttles requests, is now met with automatic exponential backoff. A new status indicator in the system tray icon warns users when throttling occurs, urging them to reduce the number of concurrent sync tasks.

Community Reactions and Known Issues

Discussion threads on the DavMail user forum reveal cautious enthusiasm. Longtime users who managed hundreds of accounts with EWS are testing Graph connections incrementally. A common pattern involves creating a second DavMail instance bound to Graph for the same mailbox, letting it run alongside the existing EWS instance, then comparing folder structures and event counts after 24 hours. So far, most report parity, though a few quirks have surfaced.

Resource mailboxes—conference rooms, projectors—require a slightly different permission set when accessed via Graph, as the API doesn’t inherit full mailbox access in the same way EWS does. Admins needing to manage shared mailboxes should ensure the authenticated user has ‘FullAccess’ or ‘Delegate’ permissions explicitly assigned, not just auto-mapping. Additionally, public folder support remains limited under Graph; users who rely on public folders for calendar sharing may need to keep the EWS listener active for those specific cases until Microsoft expands the Graph endpoints.

Broader Implications for the Windows Ecosystem

DavMail’s pivot to Graph mirrors a wider shift in the Windows tooling landscape. Utilities like MFCMAPI, OutlookSpy, and various PowerShell modules have all added or are adding Graph support. For Windows enthusiasts who value client choice—Thunderbird, em client, The Bat!, or even terminal-based mail clients—DavMail remains an essential bridge. Its permissive GPLv2 license has spawned forks and integrations, including a Snap package for Linux desktops and a Docker container that runs headlessly on Windows Subsystem for Linux.

Organizations that invested in DavMail to avoid vendor lock-in now find that continuity extends seamlessly. A department running Apple Mail on Macs or Evolution on Linux workstations can continue without retraining staff or rearchitecting their mail infrastructure. The move to Graph simply swaps out the data-fetching layer beneath the hood, preserving the same local ports and protocol interfaces. This decoupling is precisely why DavMail has thrived since its inception in 2008.

Microsoft’s Graph API itself is maturing rapidly. Recent additions include delta queries for incremental sync, which drastically reduce the number of API calls needed to stay up to date. DavMail 6.8 leverages delta tokens for mail and calendar folders, polling for changes rather than re-syncing entire mailboxes. On the Windows side, the Java runtime dependency is minimal: Oracle’s OpenJDK build or Microsoft’s own distribution work equally well, and DavMail bundles a lightweight JRE for users who prefer a single-executable experience.

Looking Ahead: The Road to Graph-Only

While DavMail 6.8 keeps EWS alive, hints in the release notes suggest that version 7.0 may drop it entirely. The rationale is straightforward: maintaining dual protocol support doubles the testing surface and delays adoption of Graph-exclusive features. The developer has called for community feedback on which EWS-specific use cases must be remedied before such a cut. The most vocal request involves handling Exchange on-premises servers, where Graph access requires either hybrid modern authentication or a dedicated on-premises data gateway. For those environments, DavMail will likely preserve a legacy EWS module that can be enabled manually.

Meanwhile, the open-source community is already contributing patches. A pull request awaiting merge adds support for Microsoft To Do tasks via the Graph /me/todo/lists endpoint, turning DavMail into a CalDAV tasks provider. Another experimental branch integrates with the Outlook calendar notifications API, giving users desktop toasts when meeting invitations arrive—without running Outlook.

For Windows administrators, DavMail’s evolution reinforces the idea that non-Microsoft clients are first-class citizens on the Microsoft cloud. The company’s own Teams client, for instance, still lacks a full CalDAV interface, but DavMail can pipe Exchange Online calendars into any CalDAV-capable tool, including Thunderbird Lightning, Fantastical, or even Obsidian with the Calendar plugin. The possibilities stretch well beyond simple email.

How to Get Started

Upgrading from a previous version is straightforward: download the new installer from the official DavMail website or source-forge project page, stop the existing server, replace the JAR, and restart. Configuration files are backward-compatible, and users can switch protocols without recreating their entire setup. The comprehensive user guide has been updated with a dedicated Graph migration checklist, including screenshots for each step.

For enterprise deployments, Group Policy and mobile device management platforms can push the installer alongside a preconfigured davmail.properties file containing the client ID and tenant identifier. Advanced options, such as disabling EWS entirely or restricting which IP ranges can access the gateway, are documented in the admin guide.

DavMail 6.8 represents more than a feature bump; it’s a strategic realignment that secures the project’s future as Microsoft closes the book on EWS. For Windows enthusiasts, IT pros, and anyone allergic to Outlook’s resource footprint, this release removes the last barrier to running a clean, standards-based mail stack on top of Exchange Online. The clock is ticking on EWS—DavMail 6.8 makes sure no one gets caught without a calendar.