(NEXSTAR) – If you use an iPhone or other iOS device, you may want to download Apple’s latest software update immediately.

On Monday, the tech giant launched Rapid Security Responses, which are meant to “deliver important security improvements between software updates.”

“They deliver important security improvements between software updates — for example, improvements to the Safari web browser, the WebKit framework stack, or other critical system libraries,” Apple explains. “They may also be used to mitigate some security issues more quickly, such as issues that might have been exploited or reported to exist ‘in the wild.'”

Apple initially announced the Rapid Security Responses last year, according to The Verge. Not only are the updates meant to target important security fixes, they’re meant to be faster to install than standard iOS updates.

They are, however, still found where traditional iOS updates are – under Settings, then General and Software Update. Mac users will find the updates under the Apple menu, then System Settings, General, and Software Update.

According to Apple, these Rapid Security Response updates are applied to your iPhone, iPad, and Mac automatically by default. If it’s needed for the update, your device will notify you to restart your device.

Apple is using letters to show the difference between standard iOS updates and Rapid Security Response updates. Once a Rapid Security Response has been applied, a letter will appear after the software version. Here’s an example of Monday’s update:

While the message about 16.4.1 (a) says it addresses “important security fixes and is recommended for all users,” Apple didn’t release security notes describing what exactly the update targets.

Rapid Security Response updates are only available for the latest versions of iOS (16.4.1), iPadOS (16.4.1), and macOS (13.3.1).