If your iPhone 16 Pro is overheating while using certain websites after updating to iOS 18.4, this could be due to background tasks like indexing, which can temporarily increase device temperature .
To address this, allow your iPhone time to complete these tasks; this process typically finishes within a few hours to a couple of days .
Additionally, close unused apps, disable Background App Refresh and Location Services, and remove your iPhone case to improve heat dissipation .
If overheating persists, consider restarting your device, updating all apps, and checking for any available iOS updates .
If the issue continues, contact Apple Support for further assistance.