Not seeing new icons

I just installed v 7.5.5.2, which I use with Ubuntu 20.04. I understand that there are new icons representing writer and calc files, but when I open a folder with .odt or .ods files in it, the icons representing those files haven’t changed. They remain as they were with v 7.4.

I’d be grateful if I could be told what I have to do to see the new icons.

Thanks,
Leslie