This is new. For the very first time, Apple has released a Rapid Security Response (RSR) update to iPhone users, with a corresponding RSR for the Mac. It represents a change in how Apple will launch smaller updates—as indicated by the number of this one. After iOS 16.4.1, you might legitimately have expected iOS 16.4.2 as the small update before iOS 16.5 lands.

May 3 update below. This post was first published on May 2, 2023.

But no, we now have a letter, and even parentheses, to attach to the numbers: here comes Apple iOS 16.4.1 (a).

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May 3 update. It’s worth noting that some users have found issues installing the Rapid Security Response update, being met with a message saying “Unable to Verify Security Response”. This seems to have been a teething problem that should have been solved by now. Forbes Senior Contributor Gordon Kelly has more on this and whether you should install the new update in his post here.

In many cases, the solution seems to have been simply to try it again immediately afterwards, or a little later in the day. Not great for the very first of a new kind of update.

To clarify, although iOS 16.4.1 (a) was the very first time Apple had released an RSR direct to all users, the capability for this was first introduced with iOS 16.2, released back in December last year.

Until now, though, they have only been deployed in developer beta releases, ensuring that devs were up to date with the latest security benefits without having to wait for the next release.

Meantime, while we wait for iOS 17 to be revealed at WWDC in June, Apple is also pressing ahead with the next big iOS 16 release, which is version 16.5. In the last 24 hours, Apple released the fourth developers’ beta of iOS 16.5, swiftly followed by the public beta. New features include a Sports tab in the Apple News app, along with a new option for Siri to start a screen recording with your voice. Oh, and sports content will get multi-viewing options, which could be a game-changer. The expectation is that iOS 16.5 will be out soon and will be one of the last iOS 16 updates, RSRs apart, before Apple’s attention is taken up with iOS 17. Stay tuned.

Which iPhones can run iOS 16.4.1 (a)?

Apple iOS 16.4 runs on all iPhones released in late 2017 or later, that is, including iPhone 8, iPhone 8 Plus and iPhone X, and this update includes features relevant to all those handsets.

How to get it

Updating is easy: open the Settings app on the device and then choose General, then Software Update. Next, choose Download and Install, it’ll all be sorted quickly. Actually, there’s something else new in this update. You need to ensure that the iPhone will download RSRs. Apple says, “iPhone or iPad: go to Settings > General > Software Update > Automatic Updates, then make sure “Security Responses & System Files” is turned on.”

What’s in the release

Here’s how Apple describes RSRs: “Rapid Security Responses are a new type of software release for iPhone, iPad and Mac. 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. They may also be used to mitigate some security issues more quickly, such as issues that may have been exploited or reported to exist.”

How do we know this is the very first RSR? Well, the very last update was iOS 16.4.1 and Apple stipulates, “Rapid Security Responses require iOS 16.4.1 or later, iPadOS 16.4.1 or later, or macOS Ventura 13.3.1 or later.”

Apple hasn’t specified what the security updates in iOS 16.4.1 (a) include. But the company says that if you don’t have security responses and system files turned on then the update will arrive later: “If you choose to turn off this setting or not to apply Rapid Security Responses when they’re available, your device will receive relevant fixes or mitigations when they’re included in a subsequent software update.”

This is an intriguing new way to update your iPhone and the prospect of quick, small updates is appealing. In my case, it certainly lived up to the rapid part of its name. The 85MB size downloaded quickly and installed in less than two minutes.