Ask HN: Multiversion backup alternative for Crashplan

I have been using Crashplan for Home for backing up my NAS. I need to find an alternative as Crashplan will stop providing this service in October 2018. I haven't been able to find a decent alternative. My main requirements: - Protection against data loss/fire/disk failure (cloud backup) - Protection against ransomware and accidental changes (multiversion backup) - Encryption before sending data - Cost effective solution (500 GB of data) - Must be able to backup a QNAP NAS - Bonus points for being able to restore data on a different device using a web application or app

The main problem in the solutions I found is that multiversion backup to the cloud is not supported from the standard QNAP software (only sync). What would you recommend?