How does the new iOS 26.4.2 affect iPhone battery life?
Apple unexpectedly released iOS 26.4.2 — just two weeks after iOS 26.4.1. The release was expected: we reported on the upcoming build a couple of days before its launch — the firmware appeared in the logs of Western publications, which traditionally signals an imminent release. But for us, users, there’s always a different question that matters: how did iOS 26.4.2 affect iPhone battery life, and does the battery drain faster after the update than before? A fresh battery life test is already available — let’s break it down.
What’s New in iOS 26.4.2
The main change in iOS 26.4.2 is the patching of a vulnerability that allowed deleted notifications to be extracted from device memory. Apple didn’t just patch the flaw for the future — the update retroactively deletes all copies of notifications that should not have remained in the system. The context is clear: in early April 2026, the FBI managed to extract deleted Signal messages from a suspect’s iPhone even after the app had been deleted. So this update is definitely worth installing as soon as possible.
The update isn’t very large and downloads quickly to the iPhone. Photo: cnet.com
- A critical vulnerability in the iPhone notification system has been patched.
- An installer bug has been fixed — the issue with iOS 26.4.1 that caused iPhones to freeze during the update is gone.
- Improvements to iCloud syncing and cellular network performance — users report faster LTE and 5G speeds.
There are no new features in this update — all new additions will appear in iOS 26.5, which is expected in May. But how well the iPhone holds its charge on iOS 26.4.2 is a question that concerns owners of all kinds of models. Especially those who remember how things turned out with iOS 26.4.1 — the test results there were extremely mixed.
iPhone Battery Life on iOS 26.4.2 — Test Results
Blogger iAppleBytes, as per tradition, tested the battery life of six iPhone models on the latest firmware: from iPhone SE 2020 to iPhone 16. The conditions were standard — identical screen brightness, the same set of tasks, and controlled battery health for each unit.
New test — new results despite the modest scope of the update
I compiled the results into a table and compared them with iOS 26.4.1, last year’s iOS 18.4.1, and the year-before-last iOS 17.4.1 — the picture turned out to be very revealing.
| Model | iOS 26.4.2 | iOS 26.4.1 | iOS 18.4.1 | iOS 17.4.1 |
|---|---|---|---|---|
| iPhone SE | 3 hours 41 minutes | 3 hours 11 minutes | 3 hours 22 minutes | 3 hours 33 minutes |
| iPhone 11 | 4 hours 49 minutes | 5 hours 18 minutes | 5 hours 31 minutes | 4 hours 55 minutes |
| iPhone 12 | 5 hours 48 minutes | 5 hours 55 minutes | 5 hours 43 minutes | 5 hours 50 minutes |
| iPhone 13 | 6 hours 22 minutes | 5 hours 26 minutes | 6 hours 41 minutes | 6 hours 40 minutes |
| iPhone 15 | 9 hours 5 minutes | 9 hours 17 minutes | 9 hours 26 minutes | 10 hours 22 minutes |
| iPhone 16 | 13 hours 58 minutes | 14 hours 54 minutes | 13 hours 47 minutes | — |
The main thing that stands out — iOS 26.4.2 has dramatically reshuffled the rankings. While in iOS 26.4.1 the iPhone SE and iPhone 13 suffered, and the flagship iPhone 16 showed nearly 15 hours of battery life, now everything has flipped upside down. iPhone battery life across different models has gone in opposite directions, making this the strangest iOS 26 update in recent memory.
- iPhone SE unexpectedly surged to the top in terms of improvement. Plus 30 minutes over iOS 26.4.1 — that’s a huge number for a device that barely lasts three hours in synthetic tests. Compared to iOS 18.4.1, the model gained 19 minutes, and it now beats iOS 17.4.1 by 8 minutes. It’s possible that Apple has finally optimized the system for the aging A13 Bionic.
- iPhone 11 — the biggest loser. Minus 29 minutes compared to iOS 26.4.1, minus 42 minutes compared to iOS 18.4.1. This is the most significant drop across the entire lineup. If you own this model and your battery isn’t exactly fresh, you’ll likely notice after updating that your iPhone drains noticeably faster than usual.
- iPhone 12 dropped only slightly — minus 7 minutes compared to iOS 26.4.1. Compared to iOS 18.4.1, it even gained 5 minutes — meaning the model essentially performs the same as it did a year ago. A stable middle-of-the-pack performer with no surprises.
- iPhone 13 — a real sensation. Remember how this model suffered on iOS 26.4 and iOS 26.4.1? In iOS 26.4.2, it gained back nearly an hour of battery life — the improvement was 56 minutes. Apple heard the complaints and fixed what had been plaguing iPhone 13 owners for several builds in a row. Admittedly, the model still doesn’t quite match iOS 18.4.1 levels (minus 19 minutes), but the gap has narrowed significantly.
- iPhone 15 — a slight minus. It lost 12 minutes compared to iOS 26.4.1 and 21 minutes compared to iOS 18.4.1. The trend is concerning: with each new iOS 26 build, this model loses a little more. Compared to iOS 17.4.1, the difference is already 77 minutes — over an hour.
And now the most unexpected result — iPhone 16. The latest flagship lost 56 minutes compared to iOS 26.4.1. Nearly an hour of battery life vanished with a single update. Considering that on iOS 26.4.1 the model showed nearly 15 hours, now it’s “only” 13 hours 58 minutes. The number is still the best in the lineup, but if this trend continues in iOS 26.5, the iPhone 16’s lead could be in jeopardy. So keep a power bank handy, just in case.
How iOS 26.4.2 Affected iPhone Battery Life — Conclusions
The short answer — for some it improved, for others it went the other way. The battery on iOS 26.4.2 holds its charge not perfectly everywhere: some models gained battery life while others lost it. And predicting which group your specific smartphone will fall into based on specs alone is difficult. Opinions are once again divided: some see improved battery life after the update, others don’t. By my estimates, the largest group consists of those who noticed no changes at all.
Does iOS 26.4.2 harm iPhone battery life? The answer is ambiguous
Battery life improved on the iPhone SE and iPhone 13, which suffered the most on iOS 26.4.1. This is a rare case where Apple managed to fix the most problematic models in a single update.
