Not Your Grandma's review for Upcart—Cart Drawer Cart Upsell

WARNING: Doesn't work with Shopify's latest default theme. I spent 1-2 hours setting it up, assuming it would work with the Horizon theme, only to find that it isn't supported. Customer support told me to switch the Dawn theme, which obviously I'm not going to do after the whole site has been built on Horizon. Very disappointed with the app and surprised it doesn't support Shopify Free Themes.