Minecraft wiki entry for Development_versions, associated text: Now emits particles when an entity is moving inside of it, or landing on it.
Freezing effect is now removed from any mobs or players that catch fire.
Mobs that have sunk into powder snow now can navigate through it.
Entities on fire now have their fires extinguished when stepping into powder snow.
Redstone dust, torches and item frames can no longer be placed on powder snow.
Gravity blocks no longer break when landing on powder snow.
While within powder snow blocks third person camera is no longer pushed to the inside of the character's head.
Mobs spawned inside Powder snow no longer have a risk of spawning underground.
Powder snow block form are no longer present in Creative Inventory anymore (MCPE-105407).
Powder snow no longer stops projectiles in Bedrock (MCPE-104940).
Lightweight mobs now can climb and navigate through powder snow blocks.
Rabbits, silverfish and endermites don't fall through powder snow blocks.
An entity walking through powder snow will make the correct step sound regardless of which block is being walked on.
Wearing Leather Boots now allows entities to climb powder snow Blocks (MCPE-105410).
Powder snow now have unique interaction sounds.