Question

I’ve an app targeted to Gingerbread. What attributes do I need to change/add in manifest file to make it run on a tablet?

Answer 1

You don’t have to add anything.
If you wan’t your app to run only in tablets you should filter the devices allowed by screen size, adding the following code to your manifest:

<supports-screens 
 android:smallScreens="false"
 android:normalScreens="false"
 android:largeScreens="true"
 android:xLargeScreens="true"
 android:requiresSmallestWidthDp="600" 
              />