package mbpfan 2.1.1-2 failed to install/upgrade: conffile difference visualizer subprocess returned error exit status 127

While upgradiing from 18.04LTS -> 20.04LTS

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: mbpfan 2.1.1-2
ProcVersionSignature: Ubuntu 4.15.0-96.97-generic 4.15.18
Uname: Linux 4.15.0-96-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
Date: Sat Apr 25 17:30:12 2020
ErrorMessage: conffile difference visualizer subprocess returned error exit status 127
InstallationDate: Installed on 2020-04-19 (6 days ago)
InstallationMedia: Ubuntu-Server 18.04.4 LTS "Bionic Beaver" - Release amd64 (20200203.1)
Python3Details: /usr/bin/python3.8, Python 3.8.2, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: /usr/bin/python2.7, Python 2.7.18rc1, python-is-python2, 2.7.17-4
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.2
SourcePackage: mbpfan
Title: package mbpfan 2.1.1-2 failed to install/upgrade: conffile difference visualizer subprocess returned error exit status 127
UpgradeStatus: Upgraded to focal on 2020-04-25 (0 days ago)
mtime.conffile..etc.mbpfan.conf: 2020-04-25T00:51:49.291146