The Galaxy J7 (2015 edition) is now receiving the Marshmallow update in Russia. The OTA is already available for download, just be sure to check in Settings for system update.
The build no. of the Android 6.0 update for Galaxy J7 is J700HXXU2BPF2, dubbed as PF2 in short. While we don’t have the changelog with us right now, but since it’s Marshmallow update being pushed on, you must — you know, for definite — download this one.
If you are unable to catch the OTA, simply download the update as firmware, which can be installed using Odin PC software very easily.
Download it form here: Galaxy J7 firmware J700HXXU2BPF2
Do note that although this firmware can be installed on all GSM Galaxy J7 devices, but because it is primarily meant for Russia, it’s equipped with modem for Russian networks and as such you may experience minor — or major! — problems upon installing the firmware on Galaxy J7 outside Russia.
You can try though, as reverting back to original firmware of your region is easy too — just download and install Galaxy J7 5.1.1 firmware for your region.