Ubuntu 18.04 LTS
See also: Ubuntu 18
TLDR: Ubuntu 18.04 LTS, also known as Bionic Beaver, is a long-term support release of the Ubuntu operating system, launched in April 2018. Designed for stability and performance, it offers five years of official support, with options for extended maintenance through Canonical's Extended Security Maintenance (ESM). Ubuntu 18.04 LTS introduced significant updates, including the GNOME 3.28 desktop environment, replacing Unity as the default interface, and improved support for modern hardware.
https://en.wikipedia.org/wiki/Ubuntu_version_history
One of the key features of Ubuntu 18.04 LTS is its use of the Linux Kernel 4.15, which brought enhancements in hardware compatibility, power management, and security. The inclusion of GNOME 3.28 offered a polished and customizable desktop experience, while additional features like native support for Snap packages simplified software installation and updates. For servers, Ubuntu 18.04 LTS provided advanced cloud integration, including support for OpenStack Queens and containerization technologies like Docker and Kubernetes.
https://ubuntu.com/blog/whats-new-in-ubuntu-18-04-lts
With a focus on enterprise and developer needs, Ubuntu 18.04 LTS supported features like Livepatch, enabling kernel updates without reboots, and improvements in security tools like AppArmor. Its extended lifecycle made it a reliable choice for production environments, especially for applications requiring long-term stability. Ubuntu 18.04 LTS continues to be supported through ESM, ensuring security and functionality for users beyond its standard support period.