Preparing for an API cleanup in 1.0.0, this version sees a lot of deprecated methods. You might also need to doublecheck your usages of enable/disable.

In order to provide an upgrade path as smooth as possible, the last feature release before 1.0.0 will be identical to 1.0.0 - except for the presence of deprecated methods and classes.

State changes (Entity add, remove, enable, disable) aren't reflected until the next system starts processing or a new World#process round begins, whichever comes first.

• Doublecheck systems that depend on being immediately informed of entity changes. (Systems are no longer immediately informed of created, altered or removed entities. Instead the change is delayed until World#process() is called, or just before the next system runs).
• Doublecheck if calls to Entity#isActive, Entity#isEnabled are still appropriate (Since entity state changes are delayed, so are state checks, you might get a 'false' when you are expecting a 'true').
• Use Entity#edit when adding or removing components.
• before 1.0.0 Replace/remove deprecated methods:
• Entity#createComponent(..) -> entity.edit().create(..)
• Entity#addComponent(..) -> entity.edit().add(..)
• Entity#removeComponent(..) -> entity.edit().remove(..)
• Entity#changedInWorld() -> remove, handled automatically.
• Entity#addToWorld() -> remove, handled automatically.
• World#changedEntity(..) -> internally tracked by artemis now.
• World#deleteEntity(..) -> invoke Entity#deleteFromWorld(). EntityEdit#deleteEntity()

Due to performance improvements there is no longer a need to have a built in enable/disable mechanic. Instead, create a component to track enable/disable state.

• before 1.0.0 Replace/remove deprecated methods with your own component solution:
• Entity#isEnabled()
• Entity#enabled(..)
• EntityObserver#disabled(..)
• EntityObserver#enabled(..)
• World#disable(..)
• World#enable(..)

Improved GWT reflection support. We now follow LibGDX naming conventions.

• @Wire arguments will suddenly start functioning on GWT. Consider if this is appropriate in your case.
• before 1.0.0 Replace/remove deprecated methods:
• @Mapper -> use @Wire instead (valid on fields and methods).
• ClassReflection#getAnnotation -> ClassReflection#getDeclaredAnnotation This returns a cross platform Annotation class, use Annotation#getAnnotation(..) to unwrap it.
• ClassReflection#hasAnnotation -> ClassReflection#isAnnotationPresent
• Same goes for Field and Method wrappers.