In User Options on the Mail tab, we can specify a default font for all mailings to use. When using this with 12 field Membership Cards, for example, Times New Roman is printed and the default is not used.
The new version of Crystal Reports used with The Raiser's Edge 7.94 can only read fonts using the True Type Format instead of the Open Type Format. To resolve the issue, convert fonts from .otf to .ttf. Free software can be found online to convert the font files. A couple of useful websites are https://everythingfonts.com/otf-to-ttf or http://www.freefontconverter.com/.