I have the exact same issue. Only the PS4 version is available when the disc is inserted and the option to download the PS5 version wants me to buy the game.

What is Ubisoft up to with this one? Was the "free upgrade" text on my game case just put there for fun?

I have the exact same issue. Only the PS4 version is available when the disc is inserted and the option to download the PS5 version wants me to buy the game.

What is Ubisoft up to with this one? Was the "free upgrade" text on my game case just put there for fun?

Same here. When I insert the disc, the option to upgrade to the PS5 version is not free. It's asking me to buy the PS5 version to upgrade.

So in essence I am only able to install and play the PS4 version from my disc. This seems like it may be a regional thing as the US guys seem to be able to do it, but here in South Africa I cannot. I see that the issue is impacting Europe too.