I put a CS:GO banner in the description of the channel in my ts server. But it is not updating. What can I do ? iuserd "Forum" version of the banner.

Those banners are static images. Once they are loaded in a web page, it stays the same until you reload the page. I don't know if it's possible to set an image to automatically reload in channel description without reloading the whole software manually over and over again, therefore this isn't practical yet in TS. However you can set the banner image of the server to refresh automatically.