We are working now on an epidemic model using fractional order derivatives (especially the Caputo definition). We actually now use another computing software to solve the system numerically. But I am wondering if Mathematica has a toolbox dedicated to solving fractional-order differential systems.
In a current version of Mathematica 12.1 there is no special solver for integrodifferencial equations. Here we show solver with using Haar wavelets for dynamic system presented in a paper
M.A. Khan, A. Atangana, Modeling the dynamics of novel coronavirus (2019-nCov) with fractional derivative, Alexandria Eng. J.
(2020), Redirecting
with differential operator replaced with the Caputo definition for fractional derivative.