[Bug 2150311] Re: error on upgrading from ubuntu 24.04.4 to ubuntu 26.04, using terminal command 'sudo update-manager -d'

[Sudhakar Verma]

Thanks for taking the time to report this bug and helping to make Ubuntu
better. We appreciate the difficulties you are facing, but this appears
to be a "regular" (non-security) bug.  I have unmarked it as a security
issue since this bug does not show evidence of allowing attackers to
cross privilege boundaries nor directly cause loss of data/privacy.
Please feel free to report any other bugs you may find.

** Information type changed from Private Security to Public

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Title:
  error on upgrading from ubuntu 24.04.4 to ubuntu 26.04, using terminal
  command 'sudo update-manager -d'

Status in ubuntu-release-upgrader package in Ubuntu:
  New
Status in update-manager-core package in Ubuntu:
  New

Bug description:
  On two different laptops I tried to perform a distribution upgrade from version ubuntu 24.04.4 towards the new version 26.04. I have first fully updated my systems, using the command 'sudo apt update', 'sudo apt full-upgrade', 'sudo apt dist-upgrade' and then I have executed the command 'sudo update-manager -d'. The result is that the availability of 26.04 is being shown and one can start the upgrade process.
  The first step in the process went allright, but during the second step in the process I got a serious error message. This second step concerns 'definition of new software channels' and esp. the calculation of changes ('calcolo delle modifiche' in Italian).

  The upgrade stops after closing the error message. Fortunately the
  error does not seem to influence or damage the existing version.

  To give you more information and allow you to judge and identify, I
  tried to include some relevant files regarding one of the systems I
  tried to upgrade. Unformtunately I can only send you one attachement,
  which is the error message itself. I have tried to  also upload:
  system information through screenfetch, the terminal screen with the
  text after executing the command 'update-manager -d', and the files
  'main-log' and 'apt-log' from the directory '/var/log/dist-upgrade',
  which were mentioned in the error message itself. I have kept these
  files and could send them if requested.

  The fact that I got the same error and error message on 2 different
  laptops reinforces the idea that it concerns a systematic error which
  is machine-independent and therefore could affect many users and their
  laptops. Of course I realise that at this stage, it could also be a
  deliberate choice of Unbuntu/Canonical not to allow premature upgrades
  from 24.04.4 at this early stage of publication of the new version,
  since normally existing users get the upgrade message only when the
  first point release is being published, normally in August. Of course
  I couldn't wait to give the new version a try. In case of a deliberate
  choice, a less alarming message (mentioning only that upgrades from
  LTS to LTS are still not active) would have been more appropriate.

  Fortunately, I have not used my daily machine, not to take too much
  risks.

  ProblemType: Bug
  DistroRelease: Ubuntu 24.04
  Package: ubuntu-release-upgrader-core 1:24.04.28
  ProcVersionSignature: Ubuntu 6.17.0-22.22~24.04.1-generic 6.17.13
  Uname: Linux 6.17.0-22-generic x86_64
  ApportVersion: 2.28.1-0ubuntu3.8
  Architecture: amd64
  CasperMD5CheckResult: pass
  CrashDB: ubuntu
  CurrentDesktop: ubuntu:GNOME
  Date: Sat Apr 25 13:22:11 2026
  InstallationDate: Installed on 2024-04-25 (730 days ago)
  InstallationMedia: Ubuntu 22.04 LTS "Jammy Jellyfish" - Release amd64 (20220419)
  PackageArchitecture: all
  SourcePackage: ubuntu-release-upgrader
  UpgradeStatus: Upgraded to noble on 2026-04-25 (0 days ago)
  VarLogDistupgradeAptHistorylog:
   Start-Date: 2026-04-25  13:20:12
   Requested-By: johan (1000)
   End-Date: 2026-04-25  13:20:12
  VarLogDistupgradeApttermlog:
   Log started: 2026-04-25  13:20:12
   Log ended: 2026-04-25  13:20:12
  VarLogDistupgradeTermlog:

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