Auto-Saving in Okular - is it possible?

Is there a way of auto-saving annotations and highlights in Okular 0.19.3?

Every time I make a change, I got to Ctrl+Shift+S to save it, and sometimes I forget it, I close the window and the software doesn't show a reminder window (as some others do in Windows).

Is there a way to configure it to auto-save, then?

Autosave is not possible without chaging the source code i.e graphically . Officially Okular has not provided this. check this out:

https://docs.kde.org/trunk5/en/kdegraphics/okular/okular.pdf

When adding an annotation to a pdf file,

Annotations are saved internally by Okular. You can export the annotated document using File -> Export As -> Document Archive

So if we close the file, and open it again in Okular, we can still see our annotations added last time. But if we open the file in another application , we can't see the annotations we added in Okular. This may be because it is .okular extension!

But sometimes it doesn't save automatically.Don't know why!

For other formats (and PDF itself), there's still the option to export annotatated documents in .okular format (File -> Export As -> Document Archive) and share them with other Okular users.

Actually, automatic internal storage is disabled in some cases, and you need to save to PDF every time you make a change. But there are warnings and a "Save or discard changes?" prompt in place for that.

The library we use to deal with PDF files, doesn't support modifying encrypted PDF files yet. If you open such a file, the "Save As" menu entry is grayed out and you are warned that you can only export as .okular file.