Pre Upgrade - Prepare 11i Financial data

Is it mandatory to complete all transactions in sub ledgers like (PO, AP, AR, CE) in 11i environment before upgrading  to R12? In other words, is financial pre migration tasks are absolutely required?

Ex-

Fin Preupgrade	Look for Un-confirmed Payment batches
Fin Preupgrade	Import all invoice from Payables Open Interface
Fin Preupgrade	Confirm or cancel all Un-confirmed Payment Batches
Fin Preupgrade	Do the Accounting, transfer all the transactions to GL from AP & AR till the date and post those transactions in GL.
Fin Preupgrade	Purge Imported Invoices from AP Interface tables
Fin Preupgrade	Make sure that no records exist in RA_INTERFACE tables.