A drifting autopilot is a common complaint on older Eagle Craft 116 models. The here refers to a recalibration of the magnetic compass and rudder feedback unit.
Technically, Eaglercraft uses to compile Java bytecode into JavaScript, allowing the game to run in a standard web browser. A "native" 1.16 version is highly complex because later versions of Minecraft require newer Java environments that aren't yet fully supported by the current browser-porting tools.
If "UPD" refers to a technical update or a specific pre-owned listing update, these typically involve: