They don't have end-to-end encryption for their contacts, calendars, tasks and notes, which is what EteSync does... Anyhow, I changed the title. Regarding the

They don't have end-to-end encryption for their contacts, calendars, tasks and notes, which is what EteSync does... Anyhow, I changed the title. Regarding the comment you were replying to: the NextCloud clients, for all I know, don't actually sync with your filesystem, they just have a UI for accessing your files.