Almost a year after the last update, Apple released a new version of iOS 12 on Wednesday, meant to patch a security hole that was recently fixed in newer versions of the OS. If you’re still using an iPhone 5S or an iPhone 6 or 6 Plus, it’s worth taking the time to update — Apple obviously doesn’t release security updates for its older software that often, so when it does, you know it’s a reasonably serious issue.

The vulnerability fixed by iOS 12.5.6 is one that could let a malicious website run unchecked code on your phone if you open it in Safari or another browser. What’s more, Apple says it’s possible someone out in the world has tried to use this exploit. While this type of warning isn’t a reason to panic — it’s relatively common for the company — it does mean that you should probably exercise a bit of caution until you update your phone.

You can download and install the update by going to Settings > General > Software Update. If your phone warns you that you don’t have enough storage to install the update, you can follow our guide on how to free up storage — some of the screens may look a bit different, but the basics will mostly be the same.

The update’s also available for a few other devices, too, such as the original iPad Air, the iPad Mini 2 and 3, and the sixth-gen iPod Touch. If you have any of those floating around, it’s probably a good idea to take some time today and update them.