Version 4.0.0 comes with HEAVILY refactored API:
- basically changed how particles are now accessed and being sent (check how-to-use doc for more info)
- many, many API changes
Because of so many changes, I suggest looking into
migration-v3-to-v4 doc to get around how to adapt to new API.
I
may support 3.x.x versions for a while, but only for limited time (few months I think at most).