Where did the Fullscreen option for PDF views go?

Hi there, since we often use uploaded PDF files (such as catalogs, price lists etc.), I really loved the possibility to view the PDF files in full screen aka Presentation mode.

With an update some time ago, this option is gone… or am I just blind and can’t see it?
How can I view files, especially PDFs in fullscreen (with pageturn functionalities, as it was there before?

Thanks very much for help!
best regards