A general program to fit global adiabatic potential energy surfaces of up to tetratomic molecules to ab initio points and available spectroscopic data for simple diatomics is reported. It is based on the Combined-Hyperbolic-Inverse-Power-Representation (CHIPR) method. The final form describes all dissociating fragments and long-range/valence interactions, while obeying the system permutational symmetry. The code yields as output a Fortran 90 subroutine that readily evaluates the potential and gradient at any arbitrary geometry. Program summary Program title: CHIPR-4.0 CPC Library link to program files: http://dx.doi.org/10.17632/8wdv87gt5x.2 Licensing provisions: GPLv3 Programming language: Fortran 90 Journal reference of previous version: C. M. R. Rocha, A. J. C. Varandas, Comput. Phys. Commun. 247 (2020) 106913 Does the new version supersede the previous version?: Yes Reasons for the new version: CHIPR-4.0 is a major extension of the previous CHIPR-3.0 code [1] which, besides diatomics and triatomics, also includes the possibility of fitting global adiabatic potential energy surfaces (PESs) of A 4 -, A B 3 -, A 2 B 2 -, A B C 2 - and A B C D -type tetratomic molecules [3]. Additionally, a new feature is that it allows the user to fine-tune ab initio diatomic curves using available spectroscopic data. Summary of revisions: • Implementation of CHIPR’s polynomial form and permutation operators for tetratomic molecules • Implementation of a direct-fit module to fine-tune ab initio potential energy curves using spectroscopic data • Automatic global minimum search on the diatomic, triatomic or tetratomic final PESs • Automatic harmonic vibrational analysis at the optimum molecular geometries Nature of problem: This version of the CHIPR code, CHIPR-4.0, provides a set of subroutines to fit global adiabatic potential energy surfaces of up to tetratomic molecules using ab initio and (for diatomics) optional fine-tuning experimental data. Solution method: CHIPR-4.0 uses the Combined-Hyperbolic-Inverse-Power-Representation (CHIPR) [2] method to interpolate and extrapolate ab initio data points. Additional comments including restrictions and unusual features: For triatomic and tetratomic fits, the user must supply subroutines containing the analytic forms defining the sum of two- and two-plus-three-bodies, respectively. These are utilized internally to calculate (from ab initio data) the corresponding three- and four-body energies to be fitted. The current version of this code is strictly based on single-sheeted analytical PESs. High-accuracy in diatomic refinements is currently limited to the 1 Σ single-curve case. References [1] C. M. R. Rocha, A. J. C. Varandas, Comput. Phys. Commun. 247 (2020) 106913 DOI: 10.1016/j.cpc.2019.106913 [2] A. J. C. Varandas, J. Chem. Phys. 138 (2013) 054120 DOI: 10.1063/1.4788912 [3] C. M. R. Rocha, A. J. C. Varandas, Phys. Chem. Chem. Phys. 21 (2019) 24406 DOI: 10.1039/C9CP04890A