In this post i will guide you on How To Downgrade AT&T Galaxy Tab S2 9.7 (T817A, T818A) From Android Nougat To Marshmallow (Rollback). Earlier Samsung had released Android Nougat for AT&T Galaxy Tab S2 9.7 (T817A, T818A) . Check this link if you want to upgrade to Android Nougat (May Security Patch Build).
AT&T Galaxy Tab S2 9.7
Along with AT&T Galaxy Tab S2 9.7 T818A received Android Nougat update, AT&T also started rolling the latest Android 7.0 Nougat update for AT&T Galaxy Tab S2 9.7 with model number SM-T818A. The new update bumps the build version to T818AUCU1BQE2 which is based on Android 7.0 Nougat. The update has started rolling