How to use structures?!

[#1]

I'm trying to get grid backup status from the wapi but cannot figure out how to use structures.. There are no examples at all. I found grid object and it has scheduledbackup : Scheduled backup settings -struct.

I can get grid backup config with 

https://<host>/wapi/v2.12/grid?_return_fields%2b=scheduled_backup,

but it does not tell me when is the latest backup done or what's its status.

I tried to get grid backup status with

https://<host>/wapi/v2.12/grid

-d 

{   "scheduled_backup": [

      {

         "_struct": "scheduledbackup",

         "status" : "FAILED"

      }

   ]

}

to see the failed ones. Not working. How do I get the status and/or timestamp of the latest grid backup?

Also, I'm wondering how to know what wapi version to use.