Ubuntu 24.04 LTS remains fully supported, but Ubuntu 26.04 LTS ships the Linux 7.0 kernel and updated security defaults. This guide upgrades a live Ubuntu 24.04 server to Ubuntu 26.04 LTS in-place using do-release-upgrade , handling the auxiliary SSH daemon, configuration file conflicts, and obsolete package removal. By the end, you'll have a running Ubuntu 26.04 system with the kernel version confirmed.

Prepare for the Upgrade

1. Update the APT package index and upgrade all installed packages:

$ sudo apt update $ sudo apt upgrade -y

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2. Remove obsolete packages:

$ sudo apt autoremove -y

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3. Install the upgrade manager:

$ sudo apt install update-manager-core -y

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Open the Auxiliary SSH Port

The do-release-upgrade tool starts an auxiliary SSH daemon on port 1022.…