I am having problem connecting from * Mozilla Thunderbird, Lightning on windows
You should ask on GNU Health forum
WebDAV has been removed from Tryton, so this is a pure GNU Health issue. Like Cédric said, I think you would be better helped through the GNU Health channels.
From what veesion because the webversion still display calender
Since version 4.4 https://discuss.tryton.org/t/migration-from-4-2-to-4-4/264