Bad news first: no new content for Cats Hidden in Jingle Jam this year. I've reached out to Yogscast earlier in the year and they were interested in bringing another level but I was then too busy myself to keep reminding them about it.
You can still donate for charity though for the next two weeks:
https://www.jinglejam.co.uk/
Now the good news: there is fresh Christmas content! Cats Hidden in Christmas got a More Merry Levels DLC with four brand-new levels and 400 cats to find! :)
https://store.steampowered.com/app/2933990/Cats_Hidden_in_Christmas/
Peace & Love
Patrick