Hey bot, I'm playing on 1.14, but it wasn't available in the list.
Chunks of the world that were already loaded won't have the updates. In order to get the new content, you have to walk into areas you haven't been yet, so new chunks load with the new stuff.
It sucks, but at least you can get the stuff. Exploring farther or moving your house is better than having to make a new world. 😛
I was just recently having this problem, but disabling VSYNC, updating my NVIDIA drivers, and reinstalling Minecraft seemed to fix it. Probably just for me though, I'm sure this issue still exists for a lot of people.