Baïkal is a free, open-source application that is used to back up and sync data between multiple computers and devices. It is designed to be easy to use and manage, while providing users with the ability to secure their data in the cloud. Baïkal also provides users with advanced features such as version control and file sharing. With version control, users can store multiple versions of their data, allowing them to easily revert to a previous version if something goes wrong. Baïkal also provides users with secure file sharing, allowing them to share files with others without having to worry about the data being exposed. Baïkal is available for Windows, Mac, and Linux, making it a great choice for those who need a reliable backup and sync application.
Radicale
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Xandikos
It seems that some of the features missing in Baikal are implemented here.