It comes with critical security patches to fix vulnerabilities detected in iPhones.

It fixes a loophole in the iOS user interface that allowed a person with physical access to an iPhone to view sensitive content without the passcode.

It also addresses a serious vulnerability in the iPhone that allowed a threat actor to send malicious content through Bluetooth to target users with a denial of service (DoS) attack.

The iOS 26.3 update also fixes the issue of abrupt closure of the app when processing a malware-laced media file.

Apple iPhone 17 Pro Max.

There were serious issues in the CoreMedia kit, which attackers exploited by sending a maliciously crafted file to iPhones and while processing it, they were able to target victimss denial-of-service attack or potentially steal memory contents. This has been fixed with improved memory handling capability on the iOS 26.3 update.

Similar vulnerabilities were detected in Game Centre, ImageIO kit, Kernel, LiveCaption feature, Photos app, Sandbox Profiles, Screenshots, Shortcuts, Spotlight, Storekit, UIKit, VoiceOver, WebKit, and more, compromising the iPhone's security and revealing personal details to attackers. All these issues have resolved in the iOS 26.3 update.

iOS 26.3 update.

List of iPhones eligible for iOS 26.3 update:

iPhone 16e, iPhone 16, iPhone 16 Plus, iPhone 16 Pro, iPhone 16 Pro Max, iPhone 15, iPhone 15 Plus, iPhone 15 Pro, iPhone 15 Pro Max, iPhone 14, iPhone 14 Plus, iPhone 14 Pro, iPhone 14 Pro Max, iPhone 13, iPhone 13 mini, iPhone 13 Pro, iPhone 13 Pro Max, iPhone 12, iPhone 12 mini, iPhone 12 Pro, iPhone 12 Pro Max, iPhone 11, iPhone 11 Pro, iPhone 11 Pro Max, and iPhone SE (2nd gen).

Apple has rolled out a similar iPadOS 26.3 update with bug fixes and security patches to all eligible iPads.

List of Apple iPads eligible for iPadOS 26.3 update:

iPad Pro (M4), iPad Pro 12.9-inch (3rd generation and newer versions), iPad Pro 11-inch (1st generation and newer versions), iPad Air (M3), iPad Air (M2), iPad Air (3rd generation and newer versions), iPad (A16), iPad (8th generation and newer versions), iPad mini (A17 Pro), and iPad mini (5th generation and newer versions).

Here's how to install iOS 26.3/iPadOS 26.3 on iPhones and iPads:

As noted earlier, the update is very big, and users are advised to rely on Wi-Fi to download it. And, ensure the device has a little over 50 per cent battery life before starting the installation process.

Via OTA (Over-The-Air)

Prerequisite: Users who want to install the update directly onto the device through OTA, make sure there is enough storage space and the device has more than 50% battery life, before initiating the download of the new iOS/iPadOS update.

Step 1: Settings >> General >> Software update

Via manual installation through Apple iTunes

Prerequisite: Back up your iPhone/iPad to iCloud or iTunes before initiating the download procedure. Also, your PC must have the latest version of the iTunes app. If not, go to About, then check for Updates, or visit iTunes.com.

Step 1: Launch iTunes on your Mac or PC.

Step 2: Insert your iPhone/iPad if it isn't already.

Step 3: Tap on the iPhone/ iPad in the top left navigation.

Step 4: Tap on the Check for Update button in the first section that contains information about your device, and alternatively, you can click Restore instead if you'd like to do a clean wipe with updated software.

Step 5: An update should be recognised, click on Download and Update in the pop-up menu and agree to the terms and conditions.

Step 6: Unlock your device with your passcode if prompted to continue with the upgrade.