Did You Disable Apple Intelligence On Your iPhone? iOS 18.3.1 May Have Turned It Back On

Some users on Reddit have expressed frustration with this development, reporting that the installation of iOS 18.3.1 toggled on Apple Intelligence, which they had to toggle off manually. However, the subsequent iOS 18.3.1 update, intended to address a USB port security flaw, turns on Apple Intelligence again.

This problem isn't peculiar to iPhone users. Mac users have also reported that updating to macOS 15.3.1 Sequoia automatically enables Apple Intelligence. If you'd like to disable it on your MacBook, our guide (linked above) provides instructions on how to do so.
Adding to the confusion, some users who updated to iOS 18.3.1 couldn't find the toggle to disable Apple Intelligence. This is because Apple intelligence is not available to all iPhone users. So, if you use an iPhone XR or later versions made before iPhone 15, you won't find Apple intelligence on your iPhone. However, if you use an iPhone 15 or a newer version, you will have access to it. It's possible this whole situation is just a software glitch that Apple will fix in a future update.