REST2 implementation in 2018.3 version

GROMACS version: 2018.3
GROMACS modification: Yes/No
Here post your question Does this version require modifications to the Forcefield for REST2 simulation?

No, you use which ever FF you are using as it is, it is just a replica exchange method.

Thank you for your help!!

Is REST2 and Hamiltonian replica exchange are same?
is it implemented in gromacs version 2020?, and if I want to run Hamiltonian replica exchange only using gromacs without plumed is it possible?