Cannot upgrade

[Madwesh J Devadiga]

An unresolvable problem occurred while calculating the upgrade.

 This was likely caused by:
 * Unofficial software packages not provided by Ubuntu
Please use the tool 'ppa-purge' from the ppa-purge
package to remove software from a Launchpad PPA and
try the upgrade again.

If none of this applies, then please report this bug using the command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. If you want to investigate this yourself the log files in '/var/log/dist-upgrade' will contain details about the upgrade. Specifically, look at 'main.log' and 'apt.log'.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubuntu-release-upgrader-core 1:20.04.41
ProcVersionSignature: Ubuntu 5.15.0-67.74~20.04.1-generic 5.15.85
Uname: Linux 5.15.0-67-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.25
Architecture: amd64
CasperMD5CheckResult: skip
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Sat Mar 25 21:10:20 2023
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to focal on 2023-03-25 (0 days ago)
VarLogDistupgradeTermlog:

[Tom Reynolds (tomreyn)]

The message is correct, you have non Ubuntu packages or package versions installed, which are likely causing conflicts.

Quote from attached file VarLogDistupgradeMainlog.txt:

Foreign: libignition-cmake2-dev libignition-math6 libignition-math6-dev nodejs python3-bloom python3-catkin-pkg python3-catkin-pkg-modules python3-colcon-argcomplete python3-colcon-bash python3-colcon-cd python3-colcon-cmake python3-colcon-common-extensions python3-colcon-core python3-colcon-defaults python3-colcon-devtools python3-colcon-installed-package-information python3-colcon-library-path python3-colcon-metadata python3-colcon-notification python3-colcon-output python3-colcon-override-check python3-colcon-package-information python3-colcon-package-selection python3-colcon-parallel-executor python3-colcon-pkg-config python3-colcon-powershell python3-colcon-python-setup-py python3-colcon-recursive-crawl python3-colcon-ros python3-colcon-test-result python3-colcon-zsh python3-rosdep python3-rosdep-modules python3-rosdistro python3-rosdistro-modules python3-rospkg python3-rospkg-modules python3-vcstool ros-build-essential ros-dev-tools rti-connext-dds-6.0.1

To upgrade Ubuntu, please first ensure you have a clean installation with only supported packages installed.

Support is available in two forms:
* commercial: https://ubuntu.com/support
* community: https://ubuntu.com/community/support