Try to upgrade ubuntu to 20.04 from 18.04, but software updater doesn't show the upgrade option. So I tried to do that in command line.
after do the following commands:
sudo apt update sudo apt upgrade sudo apt dist-upgrade sudo apt autoremove sudo do-release-upgrade -d -f DistUpgradeViewGtk3
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.
any ideas for that? Thanks