The ATF FFL Regulations Guide (5300.4) has been updated after 9 long years.

PDF: https://www.atf.gov/sites/default/fi...14_edition.pdf
Android/iPhone (.epub): https://www.atf.gov/sites/default/fi...atf_ffrrg.epub
Kindle: https://www.atf.gov/sites/default/fi...atf_ffrrg.mobi

Doesn't look like there is a way to order it for free at this time.