package unattended-upgrades 1.1ubuntu1.18.04.7~16.04.3 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[Kai Nehm]

During installation of upgrade to version 16.04

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: unattended-upgrades 1.1ubuntu1.18.04.7~16.04.3
ProcVersionSignature: Ubuntu 4.4.0-166.195-generic 4.4.194
Uname: Linux 4.4.0-166-generic i686
.var.log.apt.history.log:

ApportVersion: 2.20.1-0ubuntu2.20
Architecture: i386
Date: Mon Nov 4 11:03:07 2019
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2013-12-05 (2159 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release i386 (20130424)
PackageArchitecture: all
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.6
 apt 1.2.32
SourcePackage: unattended-upgrades
Title: package unattended-upgrades 1.1ubuntu1.18.04.7~16.04.3 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to xenial on 2019-11-04 (0 days ago)
mtime.conffile..etc.apt.apt.conf.d.50unattended-upgrades: 2019-04-30T12:03:15