We will show you how to download and install the official android 6 marshmallow for the SM-T710, T715, T810 and T815 variants of the Samsung Galaxy Tab S2 tablet. All you need to have tab s2 TWRP or ODIN on your computer.
Here you have the link(for sm-t710): T710XXU2CPD9_T710BTU2CPD9_BTU.zip
Just keep in mind that after upgrading from lollipop to marshmallow, you will loose root and TWRP, but you can later install TWRP on your own.
->Root the tablet. (Recommended)
->Install TWRP (Recommended but I think it isn’t needed)
->Enable USB Debugging on your tab.
->Make sure you have Samsung drivers installed on your PC.
->Download and extract the zip file to get the firmware file which is in .tar.md5 extension.
->Download and extract Odin from here: Odin3_v3.10.7.zip
1->Turn off your tab and boot it into the Download Mode. To do this, turn off your device and then press and hold Volume Down + Home + Power buttons simultaneously for 2-3 seconds. When you see the warning screen with a yellow triangle sign, press the Volume Up/Down key to enter Download/Odin mode.
2->Download the required Odin.zip file and extract the file on your PC. You will get the Odin3_v3.10.7.exe file. Open it as the administrator to get to the Odin window.
3->Connect your Galaxy device to the computer using the USB cable.
4->When you connect the device, the ID: COM port on Odin will turn Blue. You’ll also see“Added!!” message to indicate successful connection. If Odin des not detect your tab, try to reinstall drivers, try another USB cable and another USB port.
5-> Check "AP" box and click on AP. A window will pop up, just go to the folder where you extracted the firmware and select T710XXU2CPD9_T710BTU2CPD9_HOME.tar.md5 file (name may vary according to device model)
6->Now Odin is checking MD5 and will freeze for a minute or so, but don’t worry, just let Odin work.
7->Click on the "Options" section and make sure that only the Auto Reboot and F. Reset Time boxes are checked. (Do not, in any case, check Re-Partition box).
8->Now, click the Start button on Odin to begin firmware installation.
10->Once you get a PASS! message on Odin, your device will restart. It’s the green signal that indicates a successful installation.
11->Once our device restarts, you can disconnect it.
12-> Enjoy Marshmallow. You can now root your Tab S2 by following this procedure.