That doesn't mean there's no content - it means that you aren't following the instructions in the changelog. It is very clearly stated where you need to go and what you need to do. In the case of the new boss, for example, you need to go to Lyx's cottage, like it says, and then summon Jessica just like you do for every single other Boss Girls fight in the game.
If you get to the cottage and there's no option to summon Jessica (and it's not night) then you haven't downloaded the latest version. Which would certainly explain why you can't find any new content.