More info - https://www.minecraftforum.net/news/60702-minecraft-java-edition-1-13-1-releasedCHANGES
Performance optimizations
Added dead coral
Fish now have a 5% chance of dropping bonemeal when killed
Squids now only spawn in rivers and oceans
Added a concept of force-loaded chunks to the game, and a command (/forceload) to toggle force-loading on and off