• For browser builds, the global export was renamed to XState (previously: xstate).
• The data property of the StateNode config is now an "Assigner" or "PropertyAssigner" instead of any.
• The new State() constructor now takes an object with properties for each parameter, instead of positional arguments.
• New static method: State.create({ ... }) which does the same as above.
• The error(...) action creator now takes src as a second argument. For errors from an invoked service, the service ID will populate the src.
• onError: ... transition property added to invoke config.
• Numeric targets are now being coerced to strings, to resolve edge-case issues e.g., 3 !== '3' when selecting state transitions.
• actionTypes.null is now actionTypes.nullEvent, which alleviates some autocomplete issues in VS Code, etc.
• Instead of params and content, data will be used (polymorphic property - can take an "Assigner" or "PropertyAssigner")
• Done data is now correctly passed to the 'done.state' event. #224
• The process.env.NODE_ENV check will no longer produce errors in browser environments. #227
• The Machine interface was renamed to StateMachine to prevent naming conflicts. #231
• History state edge-cases are now resolved, and usage of the history property to indicate a history state is deprecated (use type: 'history' instead).