upgrading of samsung of 2.3.6

Solution
If the phone doesn't show the availability of an update in the "Settings" then that phone cannot be updated. Now it may be able to have the Android version changed to a newer one, if the device is rooted, however that isn't something I would personally suggest. Not just because the newer OS may not even work correctly on an older device, but that you risk bricking it as well. You would do better to get a newer device that has the features you want.
If the phone doesn't show the availability of an update in the "Settings" then that phone cannot be updated. Now it may be able to have the Android version changed to a newer one, if the device is rooted, however that isn't something I would personally suggest. Not just because the newer OS may not even work correctly on an older device, but that you risk bricking it as well. You would do better to get a newer device that has the features you want.
 
Solution