Moon+ Reader Pro Font PDF help

[Misterhabs]

I've been using Moon Reader Pro for several years. When I transitioned to a new tablet recently, some PDFs stopped displaying fonts correctly. I used to get a warning that a font was missing and was given a prompt to download it so things would display properly, but that function seems to be gone. How can I get it back? Is that even still possible? Is there a way to determine what fonts are embedded in a pdf or at least figure out what fonts I'd need to download to the sdcard/fonts folder so Moon Reader will display things correctly?