Convert PDFs to a Classic Compatible format (PDF 1.2)

You must have Brew installed.
Use brew to install ghostscript.

The following command will convert all PDFs in the current and subdirectories to PDF 1.2 with a "2" at the end of the file. You can then delete all .pdf files and rename all .pdf2 files to .pdf, or move them, whatever you may want to do.
------------------------------------------------------------------------------------------------
find ./ -name "*.pdf" -execdir ps2pdf12 {} {}2 \;