Just days after the release of iOS 10.3, Apple has pushed out an update for iOS 10.3.1 in order to fix a significant security issue that made iOS devices vulnerable to attacks sent via Wi-Fi.

The emergency patch addresses a vulnerability that would allow an attacker within range of an at-risk device to exploit a flaw in the operating system that would allow for arbitrary code execution that could attack the Wi-Fi chip in the device.

Read: How To Downgrade From iOS 10.3 To iOS 10.2.1

The issue appears to be the residual effect of a similar vulnerability that was supposedly patched with iOS 10.3. That version of the exploit allowed an attacker to execute arbitrary code with kernel privileges, meaning it could affect the entire operating system.

The vulnerability patched by the update to iOS 10.3.1 affected devices with a Wi-Fi chip. That includes the iPhone 5 and later, iPad 4th generation and later and iPod touch 6th generation and later.

In a support documentation for the update, Apple credited Google Project Zero —Google’s team of security researchers—for spotting the issue.

The patch to iOS 10.3.1 also fixes an apparent issue that kept old iOS devices from downloading iOS 10.3 as an over-the-air update. 32-bit devices including the iPhone 5, 5C and fourth-generation iPad were affected, but will now be able to download the update normally.

Read: iOS 10.3 Features: How To Change App Icons

How To Update To iOS 10.3.1

iOS 10.3.1 can be downloaded directly to your iOS device if you are connected to a Wi-Fi connection. This can be done by going to the Settings app, tapping “General” and tapping “Software Update.” An option to download and install should appear.

However, given the primary issue iOS 10.3.1 fixes has to do with potential security threats for iOS devices connected to Wi-Fi, you may choose to install the update via iTunes. Make sure your iTunes is up to date, then connect your iOS device to your computer via USB.

In iTunes, select your device’s icon from the upper left bar. Click on the Summary tab and click “check for update.” Click “Download” and iTunes will begin downloading the update. A guide of on-screen prompts will lead you through the process to complete the update.