Samsung is one of the biggest Android providers of this modern age, but this doesn't mean that the company is going to have the latest version of Android first. For that, look to Android's creator of Google and their Nexus series. However, the latest version of Android 7.0 (also known as Nougat or Android N) is coming, even if the latest version of Android 6.0 (also known as Android M or Marshmallow) isn't on some Samsung devices for some carriers. This is the latest news about Android M Version 6.0 Marshmallow and Android Nougat Release Date for Samsung Galaxy S7, S6, S6 Edge, S6 Edge +, Note 7, Note 5, Note 4, Note 3, and S5 on Verizon, AT&T, T-Mobile, US Cellular, and Sprint.
According to Trusted Reviews, the first Samsung phones to receive Android N is going to be the flagships, starting with the Samsung Galaxy S7, the Galaxy S7 Edge, as well as the Samsung Galaxy Note 7. The second wave will probably occur on the Samsung Galaxy Tab Pro S as well as the whole Galaxy S6 family.
So when will Nougat be coming? According to Know Your Mobile, it took Samsung five months to sort it its first Marshmallow update, because Marshmallow launched on September 29th 2015, but didn't show up on the Galaxy Note 5 from Verizon until March 3, 2016. Keeping that in mind, it might take quite a while and we can probably just assume that it will show up sometime around Q1 2017.
However, it is possible that the Nougat update could come sooner rather than later. There are reports that Nougat will be coming to Google's newest devices first. By that, I don't mean the new devices that will be coming sometime in the fall of 2016, but the Nexus 5X and Nexus 6P, which came out last year.
As far as Marshmallow is concerned, Samsung has been pretty good at getting it to their consumers. The Galaxy S7, S7 Edge, and the Note 7 had it pre-installed, and devices like the Galaxy S6, the S6 Edge, Galaxy S5, Galaxy Note Edge, and Galaxy Note 4. The Note 5 has been updated in the United States, for certain carriers. The Galaxy S6 Edge Plus is appearing on some markets, but it is not known if it will appear on the Galaxy S4, Samsung Galaxy Alpha, and the Galaxy Note 3. So, will the Galaxy Tab S2 receiving the update to Android on 9.7 and 8.0 inch sizes get it? That is apparently part of the plan, not to mention the Galaxy Note Pro 12.2.
If you own a "newer" Samsung devices are encouraged to check your "Settings" and "System Updates" to see if Marshmallow is ready to download OTA. This upgrade might not be ready depending on your U.S. carrier, as it has been shown that certain carriers receive the Android upgrade before others, with no real pattern. The same goes for Nougat, when it finally comes out.