After nearly 2 years of development Xfce 4.18 was released a few days ago on December 15th. This release has already been covered in detail by most news websites like OMGUbuntu and others. The detailed changelog can be found on the official Xfce website.
Install
To install Xfce 4.18 on Xubuntu 22.04 or 22.10, add the Xubuntu Staging PPA, upgrade your system, and reboot.
sudo add-apt-repository -y ppa:xubuntu-dev/staging
sudo apt upgrade
reboot
Note
Install packages from this PPA at your own risk. This PPA contains the latest builds of Xfce packages from the current development build of Ubuntu (Lunar Lobster). It is less well-tested than the packages in the official Ubuntu repositories. I have been using this PPA for a long time without any issues, and the latest 4.18 release of Xfce is working fine on Xubuntu 22.04.