Samsung has been updating the Galaxy S6 and Galaxy S6 Edge units around the world to Nougat in recent months, and some that are getting their update just now, such as those in the Netherlands, are also getting their May security patches along with the software package. The update going out to unbranded and unlocked units in the Netherlands bears the build number G920FXXU5EQE8, while T-Mobile handsets are getting the version G920FXXU5EQB3, and Vodafone devices are receiving the build G920FXXU5EQBG. They're all the same update for the most part; the normal set of Nougat features enhanced with the Grace UX introduced by the Galaxy Note 7 on top, with just a few carrier customizations here and there, bundled together with the May Security Update from Google. Unbranded units can expect to download about 1,138MB, so branded units should be expecting a similar download size.
All Galaxy S6 and Galaxy S6 Edge units that have gotten their Nougat updates thus far have all received the same clean, white UI that graces the Galaxy S7 and Galaxy S8 families, along with the wealth of new features that come with it, such as enhanced multi-window mode and battery life tweaks. On the security side of things, the May security patch comes with updates from both Google and Samsung. Users can expect to see a grand total of 65 security fixes. Out of those, 54 were packaged by Google, and 11 of them are from Samsung.
The update should be live and rolling out to all of the Galaxy S6 and Galaxy S6 Edge variants mentioned above. If you happen to be in the Netherlands and also own one of those models, you'll want to free around 3GB of space on your device, then check for the update in the About device section of your Settings menu. If it's not there, try a reboot, or wait a day or two in case it hasn't rolled out to your territory just yet. It can't be stressed enough that you don't want your phone to shut down during an update as that could cause total inoperability. To prevent this, make sure you have plenty of battery left when starting the download process or simply plug your phone to charge during the update.