I had an email today inviting me to upgrade to PL5. The price is the same as I originally paid for the full software. So not an upgrade but an invitation to buy the product again. Not the best deal in the world then - especially when the “upgrade” really amounts to more U Point, DeepPrime and some help in using a file catalogue for those who struggle.
Check in your personal account, I have the same price as for the update from v3 to v4.