i dont advice to install new update without deleting the old game file it will cause huge lag and slow down in game i advice everyone to backup your save file
there is an app called helium you download it in google playstore for your mobile
you also need download helium on your PC from here
https://github.com/koush/support-wiki/wiki/Helium-Desktop-Installer-and-Android-...
make sure you enable USB debug for your mobile to enable it
Enabling USB Debugging on an Android Device
- On the device, go to Settings > About <device>.
- Tap the Build number seven times to make Settings > Developer options available.
- Then enable the USB Debugging option. Tip: You might also want to enable the Stay awake option, to prevent your Android device from sleeping while plugged into the USB port.
after you do all that then follow the steps bellow
here is what you do now to back up your game save file
connect your mobile to your pc by using a USB
open helium on your pc then open helium on your mobile
it will enable the helium on your mobile to work
now you can remove the USB helium should work on your mobile now
click back up and click on the game and click back up
chose to save in internal storage for free or you can save to google cloud save if you want but you need need to make 1 time payment for this then you can always save to cloud forever
you can delete your game now and install new version and use save recovery from helium