Which API version does XtremeIO support V2 or V3

We are using an XtremeIO version- 2 XMS Version: 6.2.1 and using the V3 api doc. I have observed that the array is using few V2 API and few V3 API. Exact operations as below-

We are able to do these operations using V3 API-

1. Get volumes detail. - GET /api/json/v3/types/volumes/
2. Take a protection copy - PUT /api/json/v3/commands/volume/create-protection-copy
3. Delete a protection copy. - DELETE /api/json/v3/types/volumes/

Although after checking from the network logs we observed that array is using v2 api for few operations

Can you tell us the XMS or Hardware version where all these V3 API's are supported and not V2 because in order to add this support we need to have a single source of truth for our product and cannot rely on two set of API versions on the same model