This feature is added in 8.3.1. Please refer following notes from release notes:
NEW Auto-replicate new disks appears as Disabled
When you go to Replications > Incoming, Auto-replicate new disks appears as Disabled, even though you have enabled it.
Workaround: Go to the remote site and check the status from Replications > Outgoing.
You can also run the reconfigure replication wizard and check if that option was enabled. If the option is not available, you need to upgrade components at on-prem site to 8.3.1