Minecraft wiki entry for Development_versions, associated text: Players with higher than recommended render distance settings are now prompted to change it to the recommended value
Render distance default and max settings have been updated for better performance
A prompt now warns players that they will be taken back to the main menu if they sign-in while in-game
Added caching support for subchunk requests and fixed issues with holes in the terrain
Fixed a rendering error that could occur when attempting to render a Vanilla mob in a base game version prior to the version that mob was introduced through JSON files
Most content errors and warnings will now only display once per world (MCPE-135153)