on trying to upload from 15.05 to 15.10 via an update proposed following a round of normal updates, I get the message "Es konnte nicht ermittelt werden, welche Systemaktualisierungen verfügbar sind [it couldn't be determined which system updates are available] "

[MDPC]

I have no further information. The update was stopped with the message given in the summary "Es konnte nicht ermittelt werden, welche Systemaktualisierungen verfügbar sind [it couldn't be determined which system updates are available] " and none of the three cases it proposed might be responsible are responsible:

 Dies kann verursacht worden sein durch [This can be caused by]:
 * Aktualisieren auf eine Vorabversion von Ubuntu [Updating to a preliminary/advance version of Ubuntu]
 * Verwendung der aktuellen Vorabversion von Ubuntu [Using the current preliminary/advance version of Ubuntu]
 * Inoffizielle Softwarepakete, die nicht von Ubuntu bereitgestellt wurden [Unofficial software, which wasn't provided by Ubuntu]

I currently use Ubuntu GNOME 15.04 32 bit

The package I wanted to install was the official update to Ubuntu 15.10

I expected my version to update. The above message, however, appeared instead, stopping the install.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: ubuntu-release-upgrader-core 1:15.04.14.3
ProcVersionSignature: Ubuntu 3.19.0-32.37-generic 3.19.8-ckt7
Uname: Linux 3.19.0-32-generic i686
NonfreeKernelModules: wl
ApportVersion: 2.17.2-0ubuntu1.7
Architecture: i386
CrashDB: ubuntu
CurrentDesktop: GNOME
Date: Thu Nov 5 22:40:36 2015
InstallationDate: Installed on 2014-06-07 (515 days ago)
InstallationMedia: Ubuntu-GNOME 14.04 LTS "Trusty Tahr" - Release i386 (20140416.2)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to vivid on 2015-11-05 (0 days ago)
VarLogDistupgradeTermlog:

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.