Yes, updating to iOS 18.3.1 is highly recommended due to a critical security vulnerability (CVE-2025-24200) that allows attackers with physical access to a locked device to disable USB Restricted Mode. This mode is essential for preventing unauthorized data access through the USB port when the device is locked.

Regarding battery performance post-update, some users have reported increased battery drain after installing iOS 18.3.1. For example, an iPhone 15 Pro user observed a drop in battery health from 99% to 97% within a few days following the update. However, experiences vary; others have noted improvements in battery life and performance after updating. You can refer to more here: https://www.youtube.com/watch?v=GSirICVsIUU