In this talk we introduce DRAGON2, the new version of the public
software package designed to study Cosmic Ray (CR) propagation in the Galaxy. Our
aim is to illustrate the approach followed in the writing of the code and to
present its most important features. We describe the properties of the numerical
scheme that has been adopted to implement all the processes related to CR
transport and we investigate its correctness by comparing our numerical results
with a set of analytical solutions. Starting from these validation tests, we study
in detail the performances of the code by probing the different factors that
influence its accuracy and its speed under a wide range of different conditions.
The second part of the talk is focused on the propagation of leptons. In
particular, we investigate how the new features introduced in DRAGON2 in the
treatment of diffusion, energy losses and reacceleration can impact the predicted
fluxes, in comparison also with the results given by other numerical codes.