Hi all,
I am maintaining updates of BT Sync for the Drobo 5N and FS pretty much as soon as Bittorrent are releasing them for anyone who wants to be at the bleeding edge of BT Sync software!
5N: https://github.com/toby00001/btsync_drobo5n
FS: https://github.com/toby00001/btsync_drobofs
Enjoy!