尝试将ubuntu从18.04升级到20.04，但软件更新程序不显示升级选项。所以我尝试在命令行中执行此操作。
执行以下命令后：
sudo apt update
sudo apt upgrade
sudo apt dist-upgrade
sudo apt autoremove
sudo do-release-upgrade -d -f DistUpgradeViewGtk3
得到结果
sudo do-release-upgrade -d -f DistUpgradeViewGtk3
Checking for a new Ubuntu release
Failed to connect to https://changelogs.ubuntu.com/meta-release-development. Check your Internet connection or proxy settings
Upgrades to the development release are only
available from the latest supported release.
有什么想法吗？谢谢