Direct materials in classic scenario - any restriction in backend?

Dear SAP gurus,

I have read that when we use classic scenario, procurement for direct materials actually using extended classic. But as per SRM 7 EHP 2 the true classic PO (leading PO in ECC) now possible.

I just want to confirm is there any restriction in the backend side? E.g what is the minimum version of ECC that we should use for this scenario?

One more thing, I assume that in classic scenario we can have SC or external requirement goes to Sourcing Cockpit, and then we can proceed to create RFx or Auction from here rite? From here, I assume we can create PO from the response and it will create directly in ECC. is this correct?

Best regards,

John