[Bug 1791962] [NEW] don't update last version ubuntu in my computer with Ubuntu 16.04LTS, the bus informed that packages is not official. How can I solve it?

[Sianna]

Public bug reported:

The packages is not official in ubuntu 16.04 LTS

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubuntu-release-upgrader-core 1:16.04.25
ProcVersionSignature: Ubuntu 4.4.0-134.160-generic 4.4.140
Uname: Linux 4.4.0-134-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.18
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Tue Sep 11 09:26:06 2018
InstallationDate: Installed on 2016-06-28 (804 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to xenial on 2018-09-11 (0 days ago)
VarLogDistupgradeTermlog:

** Affects: ubuntu-release-upgrader (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug dist-upgrade third-party-packages xenial

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https://bugs.launchpad.net/bugs/1791962

Title:
  don't update last version ubuntu in my computer with Ubuntu 16.04LTS,
  the bus informed that packages is not official. How can I solve it?

Status in ubuntu-release-upgrader package in Ubuntu:
  New

Bug description:
  The packages is not official in ubuntu 16.04 LTS

  ProblemType: Bug
  DistroRelease: Ubuntu 16.04
  Package: ubuntu-release-upgrader-core 1:16.04.25
  ProcVersionSignature: Ubuntu 4.4.0-134.160-generic 4.4.140
  Uname: Linux 4.4.0-134-generic x86_64
  ApportVersion: 2.20.1-0ubuntu2.18
  Architecture: amd64
  CrashDB: ubuntu
  CurrentDesktop: Unity
  Date: Tue Sep 11 09:26:06 2018
  InstallationDate: Installed on 2016-06-28 (804 days ago)
  InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
  PackageArchitecture: all
  SourcePackage: ubuntu-release-upgrader
  UpgradeStatus: Upgraded to xenial on 2018-09-11 (0 days ago)
  VarLogDistupgradeTermlog:

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