For the two bottom security screws.
If you plan to install it yourself, you will need specific tools often sold in "Fix Kits":
Since official Apple Stores typically do not service the iPhone 4 anymore, you will need to rely on independent retailers: buy iphone 4 battery locally
Be cautious of "swollen" batteries (bulging cases). These are fire hazards and should be handled with extreme care. 🛠️ Replacement Tools Required
Check small electronics repair kiosks in local malls. For the two bottom security screws
To remove the internal battery connector screw.
Local shops may charge a small service fee, but some may refuse the job due to the risk of damaging aged internal ribbons. Ensure you buy a battery specifically for the iPhone 4
Ensure you buy a battery specifically for the iPhone 4 . The iPhone 4S battery has a connector on the opposite side and is not compatible.