After update, html files no longer render

I updated to the latest version, and 1) there are some bugs I need to fix in the .ini files and whatnot, but in the meantime, any file that is .html won’t render on my website. Instead, a popup dialog comes up asking to save the file. I do have some .php pages and those work fine. What did Piwik change in my setup to make html files quit working? It’s one thing if an update breaks Piwik for a few days, but I didn’t expect it to kill my website.

If anyone has insight, I’d really appreciate it!

What’s your website url? Can you reproduce with other browsers?