Btrfs and Drive ShareSync

Hi there, just got a DS216+ on ltest DSM (as local NAS) and would like to get another DSxxx as remote NAS off-site.
As far as I understand, I would need btrfs on both NAS to enable Snapshot Replication, right?
As an „alternative“ I would envisage Drive ShareSync to copy my data over to my off-site NAS. Would that (remote) NAS have to run btrfs as well and what would be the minimum DSM version on it?
Many thanks for any feedback!