Zoomforth sites used to render Microsoft PowerPoint files through Presentation tiles and sections. There have been times, however, that this feature resulted in unexpected behaviors, from inconsistent site rendering to site-editor level errors. These errors may have to do with the rich variation of elements in these files such as fonts, media, transitions, animations, etc.
In order to provide a much more consistent experience for both the site viewers and site creators, Zoomforth restricted new Presentation tiles and sections to be used only with PDFs, as of April 2018.
As described in this article, files created out of similar applications like Microsoft Powerpoint and Keynote would have to be exported as PDF first, before they can be used with Presentation tiles or sections.
Prior to the update, sites with Presentation tiles or sections associated with Microsoft Powerpoint files should still render the same as presentations in Zoomforth, but the files in these tiles or sections cannot be replaced with a different Microsoft Powerpoint file. There is no alternative option to associate a new or different Microsoft Powerpoint file with new or copied Presentation tiles or sections.