5 things to know about the iOS 15.4 update

Apple has pushed its massive iOS 15.4 update to iPhone users.

iOS 15.4 is compatible with all phones powered by iOS 15, a list that includes iPhone 6s, iPhone 6s Plus , iPhone SE , iPhone 7, iPhone 7 Plus , iPhone 8, iPhone 8 Plus , iPhone X , iPhone XS , iPhone XS Max , iPhone XR , iPhone 11 , iPhone 11 Pro , iPhone 11 Pro Max , iPhone SE 2, iPhone 12 mini , iPhone 12 , iPhone 12 Pro , iPhone 12 Pro Max and the iPhone 13 series .

Unlike the previous version of iOS 15 (iOS 15.3.1), iOS 15.4 is a major upgrade and brings new features, improvements, bug fixes and security upgrades to iPhone users around the world.

With that in mind, we want to walk you through everything you need to know about Apple's latest iOS 15 update for iPhone.

In this walkthrough, we will walk you through all the iOS 15.4 changes, software performance, iOS 15.4 issues, iOS 15.4 jailbreak status, and more. We'll start with some thoughts on iOS 15.4's performance so far.


iOS 15.4 Review

If your iPhone is currently running iOS 15.3.1, you will see the smaller iOS 15.4 download size.

For iOS 15.3.1 users, iOS 15.4 download is quite important. The download is 1.25 GB for iPhone 12 Pro users upgrading from the previous version of iOS 15. You can expect a similar size for other iPhone models.

The exact iOS 15.4 download size depends on your iPhone model and the version of iOS it is currently running. If your iPhone is running on an older version of iOS, you may see a larger download because your iOS 15.4 update includes changes from iOS updates that you skipped.

If you're upgrading from iOS 15.3.1, the installation process should take 10 minutes or less. It took about seven minutes to install on an iPhone 12 Pro that was previously running iOS 15.3.1.

We've been using iOS 15.4 on a few iPhone models for several days now and here's what we've learned about the software's performance so far:

If you encountered bugs and/or performance issues on iOS 15.3.1 or earlier version of iOS, you might want to install the iOS 15.4 update on your iPhone right now.

If you need help deciding whether or not to upgrade to iOS 15.4, please see our reasons for whether or not to install the software.

iOS 15.4 issues

iOS 15.4 update is causing issues for some iPhone 12 and iPhone 13 users. Some issues are new, some were carried over from iOS 15.3.1 and older versions of iOS 15.

The current list of issues includes installation issues, issues with first-party and third-party apps, UI lag, Exchange issues, issues with Touch ID and Face ID, and abnormal battery drain.

If you're having an issue on iOS 15.4, check out our list of fixes for the most common iOS 15 issues. We have also posted some tricks that might help you improve the performance of your phone and some tricks that might help fix iOS 15 bad battery life.

Apple recently stopped signing on iOS 15.3.1, which means you can't restore your iPhone software to the previous version of iOS 15 if iOS 15.4 starts causing problems. You also cannot downgrade to a version earlier than iOS 15.3.1.

Keep this in mind if you have a good experience on iOS 15.3.1 or earlier. Once you migrate to iOS 15.4, there's no going back.

To learn more about the downgrade process, check out our guide.

iOS 15.4 Features

Apple's major updates (xx) almost always bring new features, improvements, security patches and bug fixes to iPhone users and that's what you get from iOS 15.4. iOS 15.4 is the biggest iPhone update since the release of iOS 15 last year.

Here is the official iOS 15.4 changelog:

iOS 15.4 also comes with 36 new security patches and you can read more about them on the company's security site .

The iOS 15.4 update also quietly brought a new feature to the Notes app. The software allows users to scan handwritten text into the Notes application.

You can learn more about this change in Apple's official video above.

Jailbreak iOS 15.4

The developer teams behind the Checkra1n and Discover jailbreak tools have released versions compatible with newer versions of iOS 14, but only Checkra1n is compatible with iOS 14.5.

Unfortunately, the tools do not support iOS 15.4, iOS 15.3.1, iOS 15.3, iOS 15.2.1, iOS 15.2, iOS 15.1.1, iOS 15.1, iOS 15.0.2, iOS 15.0.1, iOS 15.0, iOS 14.8, iOS 14.7.1, iOS 14.7, iOS 14.6 or iOS 14.5.1 for now.

The latest version of unC0ver is compatible with new iPhones including the iPhone 12 series. This is great news if you've been waiting to jailbreak your new phone. Unfortunately, it is only compatible with versions up to iOS 14.3.

There's no way to downgrade your phone's software to iOS 14.5 or earlier versions of iOS, which means you're out of luck if you're upgrading or have already upgraded to newer iOS software.

And after

iOS 15.4 was the last known update in Apple's iOS 15 pipeline, so it's unclear when the next version of iOS 15 will roll out.

That being said, Apple usually puts a new version of iOS into beta testing soon after an official release, so don't be surprised if a new version emerges in the near future.

We'll let you know when we know more.