Xfce 4.18 will be coming soon to MX-21 users. We intend to add Xfce 4.18 to the main MX repositories sometime in January, and the update should come to existing Xfce users via the usual update channels. There are a lot of benefits to Xfce 4.18, including dual pane capability in thunar, updates to the Xfce settings applets, panel, and terminal, and options to have Xfce apps use the older Xfwm window theming instead of gtk3-client-side-decorations.
Users that don’t want to wait, or maybe just want to help test out the builds before we release into main, can enable our “temp” development repo. This repo is not mirrored, and only exists on our main servers. To add the repo, add the following repo definition to your sources under /etc/apt/sources.list.d
deb http://mxrepo.com/mx/repo/ temp main
sudo apt update
sudo apt dist-upgrade
and that should bring all the Xfce 4.18 related updates into your Xfce system.
We plan to be releasing updated isos including Xfce 4.18 (among other things) in January 2023.