If your touch screen is not working, there's just 2 major causes of such, either a hardware cause which might be either the phone falling on a hard object or in water which could damage the sensor board and either the screen is malfunctioning and needs to be calibrated.
If you can access the menu of the phone, i will advice you calibrate the screen first . There is no updates to download for such problem as updating the firmware of the phone would do nothing but change the settings of the phone.
To calibrate the screen, you will have to go to the phones menu, go to settings, then you select the calibrate screen, it will show you some stars to touch and once you touch them properly, then your screen will be able to work effectively.
But if you cannot access the menu because of the touch, then i will advice you repair on the phone sensor board.
