A digital product's page has a Files section. Add as many files as the product needs, and choose an option beside a file to give it only to buyers of that option, such as a PDF edition and an EPUB edition. Store now accepts EPUB, MP3, M4A, WAV, MP4, MOV, JPEG, PNG, GIF, WebP, TIFF, TTF, OTF, WOFF and WOFF2 files as well as PDF and ZIP, up to 500 MB each, and checks that each file's contents match its type.
Replace… puts a new version in place of a file. Buyers get the new file from their order, and you can choose to email each buyer who can still download it a link to their order.