It seems that the Encoder library has had a couple dozen commits, including a fair amount of additional board support, since the last release in 2016. Any chance of a new release being made to easy importing a version with this expanded support into the Arduino IDE for those less experienced users?
https://github.com/PaulStoffregen/Encoder/compare/1.4.1...master
https://github.com/PaulStoffregen/Encoder/compare/1.4.1...master