Ubuntu 19.04 (Disco Dingo) has been officially released today. This Ubuntu version is supported until January 2020. For a longer supported release, use Ubuntu 18.04 LTS instead, which is supported until April 2023.
The new Ubuntu 19.04 ships with Linux 5.0 and the latest stable GNOME 3.32, which includes significant performance improvements, experimental fractional scaling for HiDPI screens, and other updates.
The new release also includes Tracker (file index and search) by default, allows users to install proprietary Nvidia drivers from the Ubuntu installer, and much more.