How to update google play billing to library 3 or library 4?

Unity Engine
1

I received an email from google play that I have to update the google play billing library to 3 or 4 or I won’t be able to update my games. Can anyone help me in how to do so?

2

Just install Unity IAP 4.0.3 or higher, it’s already included. (actually was included in 2.2x and 3.x)