OpenNMS Horizon 23.0.3 is an update to Horizon 23.0.2.
It contains a number of bug fixes including fixes for sending notifications for events without
associated nodes, XSS issues, and more. It also includes a number of performance improvements and and update to the latest Jetty web server framework.
For a high-level overview of what's changed in OpenNMS 23, see What's New in OpenNMS 23.
The codename for 23.0.3 is Wicked Witch of the West.