Minecraft wiki entry for Development_versions, associated text: Floating water no longer generates in caves (MCPE-141424)
Meadow Flowers no longer replace blocks in villages or other structures (MCPE-141378)
Tuff blob features now generate below y=0 (MCPE-141452)
Deepslate patches no longer generate above y=0 (MCPE-141330)
Amethyst Geodes now get placed in the correct y-range during world generation (MCPE-141326)
Mineshaft tunnels can't replace Bedrock anymore (MCPE-141123)
Fixed an issue that prevented large trees from growing below y=0 (MCPE-126254)
Small Dripleaf now properly generates as part of Lush Caves biome (MCPE-125799)