[OS X TeX] PDF errors

["M. Tamer Özsu"]

I am using MacTex 2018 and have some PDF figures included. I am getting the following messages for these inclusions — anyone knows how to eliminate them? The figures are still included but the notices are annoying:

PDF inclusion: found PDF version <1.6>, but at most version <1.5> allowed

Thanks.

==Tamer
----------- Please Consult the Following Before Posting -----------
TeX FAQ: http://www.tex.ac.uk/faq
List Reminders and Etiquette: https://sites.esm.psu.edu/~gray/tex/
List Archives: http://dir.gmane.org/gmane.comp.tex.macosx
                https://email.esm.psu.edu/pipermail/macosx-tex/
TeX on Mac OS X Website: http://mactex-wiki.tug.org/
List Info: https://email.esm.psu.edu/mailman/listinfo/macosx-tex