Updates about new features, products, or events, and the process of enrolling in programs.
If you see 16.0.6228.1010, you are good. That alone confirms you're on an Insider build. :-)
Do I understand correctly that this only applies to O365 Home, Personal and University users? I have a business subscription (E3) and even several days after enrolling for First Release, I can't find a way to get beyond 16.0.6001.1038. This doesn't make me much of an Insider, and probably explains why I haven't got the badge ...