Minecraft wiki entry for Development_versions, associated text: Improved mob pathing around partial blocks (MCPE-127381).
Armor no longer renders on Pillagers and Vindicators, but are still granted armor effects (MCPE-74242).
Fixed an issue with mob rendering that caused Vindicator Axes to be visible even when they're not attacking on older Resource Packs (MCPE-123229).
More mobs will spawn underground in the Overworld.