If you've only met dog-form, then you won't be able to see karyn's menu just yet. You'll need to play the game some more and get further into the story. Then, eventually, karyn will be available
Cool, it just happened for me. "Karyn was added!" prompt, and I see her. It was honestly giving me worry because I'd put many hours into my file before getting the latest version, and it didn't update to show I was missing Relationships with new girls added, so I worried my file wouldn't work. At that weird precipice of whether to start over or not, and wanted to make sure I wasn't just wasting time. I really appreciate your response, I'll make sure to upvote you all for helping me, each comment. :D
PS: any idea which girls I need to deliberately seek out to get added, or are there spoilers to be concerned with (Yuuka for instance, I hope)?