It sounds like the worst sort of overly general advice: Make sure your device’s software is up to date. And yet it’s usually good advice, especially in this case. 

For example, a bug in iOS 17, plus a problem with some apps, including Instagram and Uber, caused many iPhone 15 Pro phones to overheating. Apple soon released an update to fix the problem.

Note that it’s normal for a phone to warm up during and after a system update as the software optimizes data in the background. However, this is a temporary temperature elevation.

Also, if you’re running prerelease software such as the iOS 26 beta or the latest Android 16 beta, it’s not uncommon for phones to run a little hot because the software usually doesn’t get optimized for battery life until just before launch.