+#### New type definitions for input data and response
+
+For cluster and thread pools, you can now only send and receive serializable `JSON` data.
+_This is not a limitation by poolifier but NodeJS._
+
+#### Public properties renaming
+
+- Thread Pool's `numWorkers` is now `numberOfWorkers`
+- Thread Pool's `nextWorker` is now `nextWorkerIndex`
+
+#### Internal (protected) properties and methods renaming
+
+These properties are not intended for end users
+
+- `id` => `nextMessageId`