Item backdrop image after update gone

[JayJayZ]

I haven't updated jellyfin for a long time due to various bugs that I read about in version 10.9.x
Two days ago I updated my server to the latest version and the backgrounds for movies, series, etc. disappeared (as in the screenshot). The logo of the series or movie was on a background that wasn't blurred. It was embedded in:

Code:

<div id="itemBackdrop" class="itemBackdrop"></div>

Unfortunately, it's empty now. Also the javascript script is different from the previous one. Is it possible to get the background of a given movie/series in this DIV tag again?