The latest version of the Department of Homeland Security National Interoperability Field Operations Guide (NIFOG) is now available for download. You can find this PDF file at this link:
The electronic version is also available at the Apple App store and Google Play for your mobile devices:
Apple
https://apps.apple.com/us/app/enifog/id1231552691
https://play.google.com/store/apps/details?id=com.saic.eNIFOG&hl=en_US&gl=US