root@NAS:~# omv-release-upgrade
Upgrading system to 3.0 (Erasmus) ...
Ign file:  Release.gpg
Ign file:  Release
Ign file:  Translation-en
Hit http://ukdebian.mirror.anlx.net jessie Release.gpg
Hit http://packages.openmediavault.org erasmus Release.gpg
Hit http://ukdebian.mirror.anlx.net jessie-updates Release.gpg
Hit http://security.debian.org jessie/updates Release.gpg
Hit http://ukdebian.mirror.anlx.net jessie Release
Hit http://ukdebian.mirror.anlx.net jessie-updates Release
Hit http://security.debian.org jessie/updates Release
Hit http://packages.openmediavault.org erasmus Release
Hit http://ukdebian.mirror.anlx.net jessie/main Sources
Hit http://ukdebian.mirror.anlx.net jessie/main amd64 Packages
Hit http://ukdebian.mirror.anlx.net jessie/main Translation-en
Hit http://ukdebian.mirror.anlx.net jessie-updates/main Sources
Hit http://ukdebian.mirror.anlx.net jessie-updates/non-free Sources
Hit http://security.debian.org jessie/updates/main Sources
Hit http://ukdebian.mirror.anlx.net jessie-updates/main amd64 Packages/DiffIndex
Hit http://ukdebian.mirror.anlx.net jessie-updates/non-free amd64 Packages/DiffIndex
Hit http://security.debian.org jessie/updates/non-free Sources
Hit http://ukdebian.mirror.anlx.net jessie-updates/main Translation-en/DiffIndex
Hit http://ukdebian.mirror.anlx.net jessie-updates/non-free Translation-en/DiffIndex
Hit http://packages.openmediavault.org erasmus/main amd64 Packages
Hit http://security.debian.org jessie/updates/main amd64 Packages
Hit http://security.debian.org jessie/updates/non-free amd64 Packages
Hit http://security.debian.org jessie/updates/main Translation-en
Hit http://security.debian.org jessie/updates/non-free Translation-en
Get:1 https://dl.bintray.com jessie Release.gpg [475 B]
Hit https://dl.bintray.com jessie Release.gpg [475 B]
Ign http://packages.openmediavault.org erasmus/main Translation-en
Get:2 https://dl.bintray.com jessie Release.gpg [475 B]
Hit https://dl.bintray.com jessie Release.gpg [475 B]
Get:3 https://dl.bintray.com jessie Release [5211 B]
Hit https://dl.bintray.com jessie Release [5211 B]
Get:4 https://dl.bintray.com jessie Release [5211 B]
Hit https://dl.bintray.com jessie Release [5211 B]
Get:5 https://dl.bintray.com jessie/main amd64 Packages [23.6 kB]
Hit https://dl.bintray.com jessie/main amd64 Packages [23.6 kB]
Get:6 https://dl.bintray.com jessie/main amd64 Packages [6637 B]
Hit https://dl.bintray.com jessie/main amd64 Packages [6637 B]
Ign https://dl.bintray.com jessie/main Translation-en
Ign https://dl.bintray.com jessie/main Translation-en
Traceback (most recent call last):
  File "/usr/sbin/omv-mkaptidx", line 68, in <module>
    cache = apt.cache.Cache()
  File "/usr/lib/python3/dist-packages/apt/cache.py", line 102, in __init__
    self.open(progress)
  File "/usr/lib/python3/dist-packages/apt/cache.py", line 145, in open
    self._cache = apt_pkg.Cache(progress)
SystemError: E:The value 'wheezy' is invalid for APT::Default-Release as such a release is not available in the sources
Reading package lists... Done
Reading package lists... Done
E: The value 'wheezy' is invalid for APT::Default-Release as such a release is not available in the sources
root@NAS:~#