cannot upgrade to next lts version
not in terminal and not in updater
current version is updated and working
main.log
2021-03-02 10:47:01,638 INFO Using config files '['./DistUpgrade.cfg.bionic']'
2021-03-02 10:47:01,639 INFO uname information: 'Linux asus-1225B 4.15.0-136-generic #140-Ubuntu SMP Thu Jan 28 05:20:47 UTC 2021 x86_64'
2021-03-02 10:47:03,335 INFO apt version: '1.6.12ubuntu0.2'
2021-03-02 10:47:03,336 INFO python version: '3.6.9 (default, Jan 26 2021, 15:33:00)
[GCC 8.4.0]'
2021-03-02 10:47:03,351 INFO release-upgrader version '20.04.29' started
2021-03-02 10:47:03,401 INFO locale: 'nl_NL' 'UTF-8'
2021-03-02 10:47:03,663 INFO screen could not be run
2021-03-02 10:47:03,811 DEBUG Using 'DistUpgradeViewText' view
2021-03-02 10:47:04,056 DEBUG enable dpkg --force-overwrite
2021-03-02 10:47:04,196 DEBUG creating statefile: '/var/log/dist-upgrade/apt-clone_system_state.tar.gz'
2021-03-02 10:47:24,126 DEBUG lsb-release: 'bionic'
2021-03-02 10:47:24,132 DEBUG _pythonSymlinkCheck run
2021-03-02 10:47:24,135 DEBUG openCache()
2021-03-02 10:47:24,136 DEBUG quirks: running PreCacheOpen
2021-03-02 10:47:24,136 DEBUG running Quirks.PreCacheOpen
2021-03-02 10:47:31,013 DEBUG Comparing 4.15.0-128 with
2021-03-02 10:47:31,016 DEBUG Comparing 4.15.0-136 with 4.15.0-128
2021-03-02 10:47:33,428 DEBUG /openCache(), new cache size 102068
2021-03-02 10:47:33,431 DEBUG need_server_mode(): run in 'desktop' mode, (because of key deps for 'lubuntu-desktop')
2021-03-02 10:47:33,431 DEBUG checkViewDepends()
2021-03-02 10:47:33,439 DEBUG running doUpdate() (showErrors=False)
2021-03-02 10:47:38,964 DEBUG openCache()
2021-03-02 10:47:45,826 DEBUG Comparing 4.15.0-128 with
2021-03-02 10:47:45,829 DEBUG Comparing 4.15.0-136 with 4.15.0-128
2021-03-02 10:47:48,245 DEBUG /openCache(), new cache size 102068
2021-03-02 10:47:48,246 DEBUG doPostInitialUpdate
2021-03-02 10:47:48,246 DEBUG quirks: running focalPostInitialUpdate
2021-03-02 10:47:48,247 DEBUG running Quirks.focalPostInitialUpdate
2021-03-02 10:48:15,322 DEBUG MetaPkgs:
2021-03-02 10:48:36,646 DEBUG Foreign:
2021-03-02 10:48:36,647 DEBUG Obsolete: google-chrome-stable
2021-03-02 10:48:36,648 DEBUG updateSourcesList()
2021-03-02 10:48:36,713 DEBUG rewriteSourcesList() with mirror_check
2021-03-02 10:48:36,714 DEBUG ['ubuntu-minimal', 'ubuntu-standard']
2021-03-02 10:48:36,714 DEBUG Checking pkg: ubuntu-minimal
2021-03-02 10:48:36,726 DEBUG Checking pkg: ubuntu-standard
2021-03-02 10:48:36,739 DEBUG examining: 'deb http://archive.ubuntu.com/ubuntu bionic main restricted'
2021-03-02 10:48:36,740 DEBUG verifySourcesListEntry: deb http://archive.ubuntu.com/ubuntu focal main restricted2021-03-02 10:48:38,056 DEBUG running doUpdate() (showErrors=True)
2021-03-02 10:49:49,653 DEBUG openCache()
2021-03-02 10:49:54,600 DEBUG Comparing 4.15.0-128 with
2021-03-02 10:49:54,601 DEBUG Comparing 4.15.0-136 with 4.15.0-128
2021-03-02 10:49:56,178 DEBUG /openCache(), new cache size 67833
2021-03-02 10:49:56,181 DEBUG need_server_mode(): run in 'desktop' mode, (because of key deps for 'lubuntu-desktop')
2021-03-02 10:49:56,183 DEBUG quirks: running PreDistUpgradeCache
2021-03-02 10:49:56,184 DEBUG running Quirks.PreDistUpgradeCache
2021-03-02 10:49:56,184 INFO checking for python-dbg
2021-03-02 10:49:56,185 INFO checking for python-doc
2021-03-02 10:49:56,185 INFO checking for python-minimal
2021-03-02 10:49:56,185 INFO installing python-is-python2 because python-minimal was installed
2021-03-02 10:49:56,186 DEBUG Installing 'python-is-python2' (python-minimal was installed on the system)
2021-03-02 10:49:56,312 INFO removing python-minimal because python-is-python2 is being installed
2021-03-02 10:49:56,314 DEBUG Removing 'python-minimal' (python-is-python2 is being installed on the system)
2021-03-02 10:49:56,315 INFO failed to remove python-minimal
2021-03-02 10:49:56,317 INFO checking for python-dev
2021-03-02 10:49:56,318 INFO checking for libpython-dev
2021-03-02 10:49:56,319 INFO checking for libpython-stdlib
2021-03-02 10:49:56,319 INFO removing libpython-stdlib because None is being installed
2021-03-02 10:49:56,320 DEBUG Removing 'libpython-stdlib' (None is being installed on the system)
2021-03-02 10:49:56,320 INFO failed to remove libpython-stdlib
2021-03-02 10:49:56,320 INFO checking for libpython-dbg
2021-03-02 10:49:58,040 ERROR Dist-upgrade failed: 'E:Fout, pkgProblemResolver::Resolve leverde defecten op. Dit kan veroorzaakt worden door vastgehouden pakketten.'
2021-03-02 10:49:58,042 DEBUG abort called
2021-03-02 10:49:58,046 DEBUG openCache()
2021-03-02 10:50:13,409 DEBUG Comparing 4.15.0-128 with
2021-03-02 10:50:13,412 DEBUG Comparing 4.15.0-136 with 4.15.0-128
2021-03-02 10:50:15,877 DEBUG /openCache(), new cache size 102068
答案1
从 lubuntu 18.04 升级到 20.04 的最佳方法是备份数据并进行全新安装。Lubuntu 不建议使用升级功能（我认为他们确保它不能从 18.04 升级）进入新的桌面环境。（如果您不喜欢新的桌面环境，您可以使用其他发行版（如 Kubuntu）并使用相同的备份来恢复数据。）