trigeek
I just upgraded Ubuntu from 17.04 to 17.10 and this broke my dokuwiki, which only showed page source. I spent ages checking on my hunch that php was not working, including going through all the upgrade warnings.
Eventually I solved the problem by completely removing php7.1 and reinstalling it. However I'm getting an error message when editing and saving content:
This page isn't working localhost is unable to handle this request.
If the browser page is refreshed it seems the editing did work, though.