I found a (dirty) workaround.
Inspecting https://www.rottentomatoes.com/m/dream_horse, you can see the sidebar that used to be on the homepage. The structure is the same as before, except that the name of the div-element is different than assumed in the rt-scraper code.

So, this is what I did to get it working:

1. Go to the node-modules/rt-scraper directory in your MagicMirror installation dir.
2. Edit index.js
3. Replace the three instances of “homepage-top-box-office” with “movies_sidebar”
4. Replace the request uri rottentomatoes.com to rottentomatoes.com/m/dream_horse
5. Restart MagicMirror and you should now see the RT movie listing appearing again.

Now, this is dirty, because of the Dream Horse link. I’m think about a better way (take the first movie on the site?) and commit to github. But for now we can at least enjoy the movie listings again.