I like and use Backblaze.
That said, Sierra came out in 2016 and I thought Crashplan’s Business plan dropped its Java applet years ago (while retaining it for the consumer plan). Can’t shed a tear when people are using deprecated OSes, sorry.
You’ll probably like Backblaze, though if you want extended versioning the price will be close to CrashPlan’s prices anyway, and there’s no Family plan.