Outlook CalDav Synchronizer is a free Outlook Plugin, that can synchronize events, tasks and contacts between Outlook and a CalDAV or CardDAV server*. Amongst others, it supports synchronisation between Google, SOGo, and Horde, and it supports 3Outlook versions 2016, 2013, 2010 and 2007.

Key Features include:

• Two-way-sync.
• Modern WPF GUI.
• Supporting OAuth2 for Google.
• SSL/TLS support, support for self-signed certificates.
• Manual proxy configuration support for NTLM or basic auth proxies.
• Auto discovery of calendars and address books.
• Configurable sync range.
• Sync multiple calendars per profile.
• Sync reminders, categories, recurrences with exceptions, importance, transparency.
• Sync organizer and attendees and own response status.
• Task support.
• CardDAV support to sync contacts (distribution lists planned).
• Google native Contacts API support with mapping of Google contact groups to Outlook categories..
• Google Task lists support (sync via Google Task Api with Outlook task folders).
• sync contact pictures, categories, notes and x509 certificates.
• Time-triggered sync.
• Manual-triggered sync.
• Change-triggered sync.
• Category Filtering (sync CalDAV calendar to Outlook categories).
• Map CalDAV server colors to Outlook category colors.
• Show reports of last sync runs and status.
• Configurable system Tray Icon with notifications.
• Bulk creation of multiple profiles.

*Tested CalDAV servers include: SOGo, Google Calendar, Horde Kronolith, OwnCloud, SabreDAV, Synology NAS, GroupOffice, one.com, Yandex, OpenX-change, Posteo, Landmarks, Kolab, Zoho Calendar, GMX, Tine 2.0, Fruux, Mac OS X Server, iCloud, Mail.ru, Radicale.