Published: November 13, 2026
After an iOS update, your iPhone may not work as expected. Buttons might become unresponsive, apps may close unexpectedly, or the screen may freeze briefly. You may also wonder whether the security fixes for Messages and Bluetooth are related.
Here is what Apple has documented. Apple released iOS 27.2.1, iOS 26.7.3 and iOS 18.7.12 on November 9, 2026. The release notes list security fixes, including fixes for Messages, Bluetooth and AirPlay pairing. They do not mention app freezes or screen glitches. This guide separates Apple’s documented security fixes from the troubleshooting steps you can try if your iPhone starts behaving strangely after an update.
Quick Fix
Start here. These two steps are a good starting point for common one-app problems.
1. Restart Your iPhone
Go to Settings > General > Shut Down, drag the slider, and wait about 30 seconds. Then hold the Side button until the Apple logo appears. If the screen does not respond at all, force restart: press and release Volume Up, press and release Volume Down, then hold the Side button until the Apple logo appears. This works on every iPhone that can install these updates.
2. Update the App That Misbehaves
Open the App Store, tap your profile icon, tap App Updates, and update the app. If it still crashes, delete it and install it again. Deleting an app can remove data stored inside it, so save anything important first.
If battery life is what changed after the update, our battery drain guide covers that separately.
What Apple Actually Fixed
Apple published a separate security page for each release. Unless a fix is marked otherwise, it appears in all three. iOS 27.2.1 and iOS 26.7.3 cover iPhone 11 and later. iOS 18.7.12 covers iPhone XS, XS Max and XR.
Apple words most of these as something an attacker “may be able to” do. That means a weakness existed and is now closed. It does not mean your iPhone was attacked.
Pairing, Bluetooth and AirPlay
- Someone within Bluetooth range may have been able to get around the limit on AirPlay pairing-code attempts.
- Someone on the same network may have been able to do the same through a second route (listed as “rapportd”).
- A malicious Bluetooth device may have been able to pair without any action from you, and someone in range may have been able to get around the pairing-code limit to pair with a device.
- Someone in Bluetooth range may have been able to corrupt process memory, caused by a use-after-free error.
- iOS 18.7.12 only: someone with physical access may have been able to pair a device with an AirPlay receiver from the lock screen.
iMessage group chats (iOS 27.2.1 and 26.7.3 only)
- A remote attacker may have been able to join an iMessage group chat and receive its messages.
- A person added to a group may have been able to see messages sent before they joined.
Other fixes
- Brotli (iOS 27.2.1 and 26.7.3): processing maliciously crafted input could lead to memory corruption.
- App Intents (iOS 27.2.1 only): an app may have been able to access sensitive user data.
Apple’s pages do not say whether any of these were used in real attacks. Installing the update is the sensible precaution.
If It Still Feels Off
Apple’s security notes do not explain slowdowns, so there is no single confirmed cause. Apple’s own advice for a slow or frozen iPhone points to everyday things, so work through these in order.
3. Check Your Storage
Go to Settings > General > iPhone Storage. Apple’s slow iPhone guide says to keep at least 1 GB free to avoid slowdowns. You can offload an app, which frees its space but keeps its documents and data, or delete it, which removes the app and its data.
4. Check Low Power Mode and Temperature
Low Power Mode (Settings > Battery) turns off some features or makes them slower, and the battery icon turns yellow. If you need full speed, turn it off. An iPhone that is too hot or too cold can also run slower, so move it somewhere more moderate.
5. Check Your Network
Many apps need the internet, so a weak or crowded connection can look like a frozen phone. Wait a moment, move to another spot, or switch to Wi-Fi. If mobile data keeps failing in several places, contact your carrier.
6. Install the Latest iOS Update
Back up your iPhone first, plug it in, and connect to Wi-Fi. Then go to Settings > General > Software Update and tap the update. If a message says more space is needed, you can let iOS temporarily remove apps. They are reinstalled automatically afterward. A VPN or proxy connection can stop the update from downloading, so turn it off if the update will not start. Apple’s security releases page lists every update and its fixes.
7. Review Bluetooth Devices and Group Chats
Go to Settings > Bluetooth and look at the list. If you see a device you do not recognize or no longer use, tap the “i” next to it and choose Forget This Device. You will need to pair it again if you want it back. In busy group chats, check who is in the thread before sharing anything private. That is general privacy advice, not a fix for the issues above.
8. Reset Network Settings (Last Resort)
Use this only if network problems survive the steps above. Go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. According to Apple’s guide:
- Previously used networks and VPN settings that were not installed by a configuration profile or device management are removed.
- The device name goes back to “iPhone”, and manually trusted certificates become untrusted.
- Wi-Fi turns off and on, so you are disconnected from your current network.
- Cellular Data Roaming may also be turned off.
- Photos, apps and other personal data are not erased.
Do not confuse this with Reset All Settings, which resets much more, including Apple Pay cards. Choose the network option only.
When to Contact Support
If one app keeps crashing after you reinstall it, contact that app’s developer.
Contact Apple Support if the whole iPhone is affected and the problem stays after a restart and an update, for example:
- the screen stays frozen after a force restart,
- the phone gets stuck on the Apple logo, or
- you think someone paired a device with your iPhone without your knowledge.
Note your iOS version and what you were doing when it started. It helps them find the cause faster.
Frequently Asked Questions
Which update should I install if my iPhone shows two options?
You may see an update for your current iOS version and, separately, an upgrade to a newer major version. Apple lists the update for your current version first, with the major upgrade at the end of the screen. Install the first to stay on your version, or choose the upgrade to move up.
Can I stop my iPhone from installing updates by itself?
Yes. Go to Settings > General > Software Update > Automatic Updates. You can have iOS install updates overnight, only download them, or neither. The option names can differ slightly between iOS versions. If you turn automatic installs off, remember to check for updates yourself, including security ones.
How do I check which iOS version I have?
Open Settings > General > Software Update. The version installed on your iPhone is shown at the top, and so is whether an update is waiting. Compare it with 27.2.1, 26.7.3 or 18.7.12 to see where you stand.
Do these updates also cover iPad?
Yes. Apple’s pages are titled for iOS and iPadOS. iPadOS 27.2.1 covers iPad Pro 12.9-inch (4th generation and later), iPad Pro 11-inch (2nd generation and later), iPad Air (4th generation and later), iPad (9th generation and later) and iPad mini (6th generation and later). iPadOS 26.7.3 covers older models back to iPad Pro 12.9-inch (3rd generation), iPad Pro 11-inch (1st generation), iPad Air (3rd generation), iPad (8th generation) and iPad mini (5th generation). iPadOS 18.7.12 covers iPad (7th generation).
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