This is evidence that the latest iOS update, version 17.0.3, addresses the problem of the iPhone 15 overheating.
Macworld
Last week, Apple launched the iOS 17.0.3 update. This update includes two important security fixes and claims to resolve a common problem of the iPhone 15 overheating. According to Apple’s release notes, the update addresses “an issue that may cause the iPhone to heat up more than usual.” However, practical tests have demonstrated that the update significantly reduces temperatures.
Based on ZDNet’s Jason Hiner’s tests, the new update reduces temperatures by up to 15 degrees during peak heat. During his review of the iPhone 15 Pro and Pro Max, Hiner encountered overheating and observed that the Pro Max reached a high temperature of 107.1 degrees Fahrenheit (41.2 degrees Celsius) while charging. He also noticed heat problems while using the Halide camera app.

ZDNet
After installing the 17.0.3 update from Apple, Hiner charged the phones and observed a peak temperature of 93.8 degrees Fahrenheit (34.3 degrees Celsius). The temperature then fluctuated between 80 and 90 degrees Fahrenheit (26.7 and 32.2 degrees Celsius). Hiner also observed that the update did not impact the performance of the phones.
Apple addressed complaints of the iPhone 15 experiencing overheating through identifying three potential reasons: intense activity while configuring a new iPhone, problems with recently updated apps, and a glitch within iOS 17. In addition to releasing the iOS 17.0.3 update, Apple is collaborating with app creators to investigate any potential performance concerns related to the A17 Pro chip in the iPhone 15 Pro and Pro Max.
For those with a recent iPhone 15, make sure to install the iOS 17.0.3 update, which includes crucial security updates. If you are planning to purchase an iPhone 15, the update should be available for installation during the initial set up process.