The next release is getting closer and closer. All the time I am mainly trying to stabilize the application after the last major changes in the documents module, and in the meantime adding smaller features. One of them is the introduction of support for PPT and PPTX files, both for viewing and indexing content.
The slides preview comes down to generating images for each slide, so there is currently no way to e.g. select and copy text from the slide, but still the preview itself should be quite helpful here in terms of verifying whether this is the right file to open or a quick preview of its contents.