Für mich selbst als Referenz 🙂
pi@raspberrypi ~ $ wget https://download-cdn.getsync.com/stable/linux-arm/BitTorrent-Sync_arm.tar.gz
pi@raspberrypi ~ $ tar xvzf BitTorrent-Sync_arm.tar.gz
pi@raspberrypi ~ $ sudo service btsync stop
pi@raspberrypi ~ $ sudo mv /usr/local/btsync/btsync /usr/local/btsync/btsync.bak
pi@raspberrypi ~ $ sudo mv btsync /usr/local/btsync/btsync
pi@raspberrypi ~ $ sudo service btsync start