[Yetanfou]

...or Owncloud [1], or Nextcloud [2], or Syncthing [3], or Seafile [4], all of them free software, none of them needing 'future discounts' like the Duple site promises to 'beta testers' since they are free software.

[1] https://owncloud.org/

[2] https://nextcloud.org/

[3] https://syncthing.net/

[4] https://www.seafile.com/