- Add `pykka.__version__` to conform with PEP 396. This deprecates `pykka.VERSION` and `pykka.get_version()`.
- Add `pykka.ActorRef.tell()` method in favor of now deprecated `pykka.ActorRef.send_one_way()`.
- Add `pykka.ActorRef.ask()` method in favor of now deprecated `pykka.ActorRef.send_request_reply()`.
- `pykka.ThreadingFuture.set()` no longer makes a copy of the object set on the future. The setter is urged to either only pass immutable objects through futures or copy the object himself before setting it on the future. This is a less safe default, but it removes unnecessary overhead in speed and memory usage for users of immutable data structures. For example, the Mopidy test suite of about 1000 tests, many of which are using Pykka, is still passing after this change, but the test suite runs approximately 20% faster.