How to Upgrade SAP PI 7.31 SP07 (Dual Stack) to SAP PO ?

Hello Experts,

Currently we are having SAP PI 7.31 SP07 Dual stack system. My questions as below,

1. Can we upgrade our current system to SAP PO (Java Only)..?

2. What would be the latest version of SAP PO to which we can upgrade our current system?

3. Is there any documentation, links available for step by step upgrade steps?

Waiting for response..!!

Thanks

Amit