Samsung Galaxy J7 has a 5.5″ display with octa-core Snapdragon 615 processor and a big 3000mAh battery. It also has 3MP rear-facing camera with an f/1.9 aperture lens, 1.5GB of RAM, 16GB of on-board storage, a MicroSD card slot, LTE and dual SIM capabilities. At the time of its launch Samsung Galaxy J7 ran on Android 5.1 Marshmallow.
Galaxy S7 is way behind in the queue to get official Marshmallow support. But Samsung users need not worry as there is CM 13 ROM which will update Galaxy J7 to Android Marshmallow. It will also give stock look and feel to the device with minimum bloat. A detailed guide on how to install CM 13 ROM on Galaxy J7 is given below.