Release 0.8.9 is a minor release and contains a bugfix for HSM, a feature for GraphSupport and changes internal cache handling:

• Bugfix #544: NestedEvent now wraps the machine's scope into partials passed to HierarchicalMachine._process. This prevents queued transitions from losing their scope.
• Feature #533: (A)Graph.draw function (object returned by GraphMachine.get_graph()) can be passed a file/stream object as first parameter or None. The later will result in draw returning a binary string. (thanks @Blindfreddy).
• Feature #532: Use id(model) instead of model for machine-bound caches in LockedMachine, AsyncMachine and GraphMachine. This might influence pickling (thanks @thedrow).