In the world of Android midrangers, one rarely expects major updates to be installed on the phone post-purchase. Manufacturers usually support their flagship or otherwise top-shelf smartphones for up to two Android builds, while midrangers and lower class devices just get a few minor patches to fix possible issues. Of course, this has been changing in recent times, as smartphone makers are looking to draw fans to their camps, and have put more effort into software support for their handsets. Sony is a good example for this, with its Marshmallow update rolling out to a wide range of Xperia devices.
Samsung does have the reputation of not keeping its midrangers up to date on the software side, but that may be changing. Thanks to a couple of certifications spotted at the Wi-Fi Alliance, we can see that there is, in fact, an Android 6 Marshmallow build running on a Samsung Galaxy A5 (2016) and Galaxy A7 (2016) out there. The 2016 run of the A series, as you probably know, consists of metal-and-glass-clad midrangers, all of which, save for the lowest tier A3, pack a fingerprint sensor, Samsung Pay support, and optical image stabilization on their cameras. The line currently has the entry-level Galaxy A3, the mid-range Galaxy A5, phablet midrangers Galaxy A7, and Galaxy A9, with a Galaxy A9 Pro also in the pipeline, though, possibly only for Eastern markets.
The fact that these smartphones all launched with Android 5.1 Lollipop months after Marshmallow was official was a bit of a disappointment. Speculations could be drawn that Samsung wanted its flagships — the Galaxy S7 and S7 edge — to be the first of its smartphones donning the new user interface and operating system. So, it makes sense that now, when the S7s are out, that Sammy would try to make it right to owners of its midrange handsets by bringing them up to speed, software-wise.
Unfortunately, we've no clue on when the update would actually roll out to the masses. Also, there aren't any certifications for the Galaxy A3 and A9 to be seen as of yet, so it may be a while.