I edited "/etc/update-manager/meta-release"
...from https to http:
[METARELEASE]
URI_LTS = http://changelogs.ubuntu.com/meta-release-lts
DEBUG_UPDATE_MANAGER=1 do-release-upgrade -c
Output:
MetaRelease.__init__() useDevel=False useProposed=False
/etc/update-manager/meta-release: https://changelogs.ubuntu.com/meta-release
/etc/update-manager/meta-release: http://changelogs.ubuntu.com/meta-release-lts
/etc/update-manager/meta-release: -development
/etc/update-manager/meta-release: -proposed
metarelease-uri: http://changelogs.ubuntu.com/meta-release-lts
MetaRelease.download()
reading file '/home/nwo/.cache/update-manager-core/meta-release-lts'
have self.metarelease_information
MetaRelease.parse()
current dist name: 'bionic'
found distro name: 'dapper'
found distro name: 'hardy'
found distro name: 'lucid'
found distro name: 'precise'
found distro name: 'trusty'
found distro name: 'xenial'
found distro name: 'bionic'
There is no development version of an LTS available.
Segmentation fault
The https error is gone, but Segmentation fault is there.