How to change orogonal icons to custom icons?

  • Used Zammad version: 5.3.0
  • Used Zammad installation type: (source, package, docker-compose, …) package
  • Operating system: Ubuntu server

Hello! Can you please how to change icons to custom icons? for example I want to change bird icon on the login page to some custom icon and so on. As I can see the path where all the icons is here:
but when I change some icons there keeping the name of the file nothing happens. Zammad shows old icons.