The Samsung Galaxy Tab S2 is currently receiving its update to Marshmallow in the U.S. The update is for both the 8- and 9.7-inch Wi-Fi-only versions of the tablet, and weighs in at over 1GB.
The Marshmallow update brings a number of enhancements and user experience improvements, including Doze, which helps cut down on battery usage. The update should roll out automatically, but you can always check in Settings to grab it manually.
Source : androidcentral