Could you please list what it unlocks and what it doesn't?

Screenshots would be nice.

Yeah I lied I thought it would have worked but no it doesnt. none of the unlocks work you have zero options for starting locations or outfits other than the dlc ones. Same thing with the weapons you get the dlc ones but you cant unlock the others through challenges and you also cant unlock the hardest difficulty due to mastery being walled off for online only. So yeah this sucks i'll hold out for a bit and hope that they update it but if not I'll be refunding.

My personal sources can confurn this, the upgrade turned out to be not very helpful for the situation.

So there's no way to properly unlock this online stuff?

This GOTY upgrade gives access to the 4 bonus campaign missions and unlocks the 3 outfits automatically,
BUT the 3 weapons have to be unlocked online (Escalation Contracts). Pic attached.

Thank you. Good to know.

And while we're here, also many thanks for creating and until recently maintaining the "GOG News and staff threads" --- an amazingly useful resource when one needs to check things past.