This release includes unified linear solver interfaces in all SUNDIALS packages, encapsulated nonlinear solvers in all SUNDIALS integrators, a reorganization of ARKode to allow for the development of new integration methods, a new ARKode stepper for two-rate explicit/explicit multirate infinitesimal step methods, Fortran 2003 interfaces to CVODE and several SUNDIALS modules, an OpenMP 4.5+ NVECTOR, managed memory capabilities for the CUDA NVECTOR, and other improvements.

A patch release v4.0.1 was also released to fix a bug in ARKode where single precision builds would fail to compile.

Read more about v4.0.0 and the complete SUNDIALS release history. Downloads are available from the SUNDIALS website and GitHub.