The version of Android OS installed on Samsung Galaxy Tab 2 device can be found using the option available as part of About section.
Step 1: Launch the Settings screen on Samsung Tab 2.
Step 2: In the Settings screen, tap the About Device option under System section.
Step 3: The About Device details will contain the Android Version as shown in the above screenshot,
If you want to upgrade the Android Version then tap the Software update option. This would check with the server for any new software update and will provide option to install the software if any available.