The wait is over. The new Ubuntu graphical installer is now available for testing. The installer is written in Google's Flutter software development kit (SDK) and promises a modern installation experience.
The biggest changes that the new Ubuntu Desktop Installer brings, in addition to the modern design on all pages of the installer, is a new "Try or install" page that includes a new "Repair Installation" option for you help repair a corrupted Ubuntu system. You can also turn off Intel RST (Rapid Storage Technology) if you are installing Ubuntu with Windows, a new disk space allocation page, and a new page to choose between Light and Dark themes.
Canonical was originally preparing more features for the new Ubuntu Desktop Installer, but has now released a basic version that can perform a normal or minimal installation without the ability to configure advanced options such as encryption or Active Directory authentication. Also, the "Time Zone" selection page seems to be missing at the moment.
As mentioned above, the new Ubuntu Desktop Installer will be available as a technical preview in the upcoming release of Ubuntu 21.10 (Impish Indri) and will offer limited features. The installer is going to completely replace the current Ubiquity Installer next year with the release of the Ubuntu 22.04 LTS version, if all goes according to plan.
Until then, you can if you want to download to try the new Ubuntu Desktop Installer. This will help Canonical improve the new application. You can download Canary daily build images of Ubuntu 21.10 (Impish Indri) from here.
Note that there are still errors in the installer, so it may not work as planned.
Ubuntu 21.10 (Impish Indri) will be officially released on October 14, 2021. It will be the first release of Ubuntu that will "wear" with the latest GNOME 41 series, the upcoming Linux 5.14 kernel, GCC 11 and LLVM 13 as default. Ubuntu 21.10 will use the current Ubiquity installer as the default installer.