A software update is required to connect to your iOS device / iPhone

On my mac I've recently updated to the latest macOS version 10.13.5 and have installed Xcode 10 (beta 1). For my iPhone X there is an update available to 11.4 but i didn't install that yet. Now there is this weird pop up on my mac that keeps appearing, that I have never seen before:

When the alert window is focused the menu in to top left corner of my screen doesn't change. So i can't tell from which application it's coming from, so I assume it's a system alert.

But the font size of the description is 12. Standard is 13. That popup doesn't look safe to me because of that and also the description is not really specific. I have 5 iOS devices connected.

I will update on my iPhone X directly and see if this popup still appears.

UPDATE

I've updated my iPhone X to iOS 11.4 but the pop up still appears.

UPDATE 2

I've found out that the popup is coming from a process called MobileDeviceUpdater

UPDATE 3

I've installed all updates to all my devices and the popup still appears.

UPDATE 4

I've sampled the process and it seems that it is an apple process.

Sampling process 14573 for 3 seconds with 1 millisecond of run time between samples
Sampling completed, processing symbols...
Analysis of sampling MobileDeviceUpdater (pid 14573) every 1 millisecond
Process:         MobileDeviceUpdater [14573]
Path:            /System/Library/PrivateFrameworks/MobileDevice.framework/Resources/MobileDeviceUpdater.app/Contents/MacOS/MobileDeviceUpdater
Load Address:    0x10d689000
Identifier:      com.apple.MobileDeviceUpdater
Version:         1.0 (1)
Build Info:      MobileDeviceUpdater-988200034100003~2
Code Type:       X86-64
Parent Process:  ??? [1]

Date/Time:       2018-06-08 14:45:55.105 +0200
Launch Time:     2018-06-08 13:28:48.013 +0200
OS Version:      Mac OS X 10.13.5 (17F77)
Report Version:  7
Analysis Tool:   /usr/bin/sample

Physical footprint:         15.4M
Physical footprint (peak):  16.1M

...

I didn't include the Call graph and the Binary images.

The binary is located at:

/System/Library/PrivateFrameworks/MobileDevice.framework/Resources/MobileDeviceUpdater.app/Contents/MacOS/MobileDeviceUpdater

UPDATE 5

I've hit the Install button and it tried to download one item but wasn't able to.

UPDATE 6

There is still nothing to update. The popup keeps appearing and fails every time I hit the Install button ...

The problem can be fixed by installing XCode beta.

This error occurs when the version of macOS (and iTunes) running on the computer is not compatible with the version of iOS on the device you're trying to connect.

Normally, updating the macOS to its current version will solve the problem. However, this won't work if the iOS device is running a newer beta version, and the Mac is not.

If you don't want to run the beta version of macOS (or downgrade the iOS device to a non-beta version), a solution is to install the beta version of Xcode.

Even though you may have no use for Xcode itself, its beta version includes the necessary software patches which will allow your existing macOS (and iTunes) to support devices running the iOS beta.

Download the Xcode beta from: https://developer.apple.com/download

The xip file will (eventually) unarchive into the full Xcode app. Drag it into your Applications folder, and then be sure to start Xcode. At that point it will install the necessary software components for the latest iOS beta. When it asks to open or create a project, you can quit Xcode.

iTunes should now recognize the iOS device.

Reference: https://ios.gadgethacks.com/how-to/fix-software-update-is-required-connect-your-iphone-warning-your-mac-0185898/

I received this error today. I have macOS Mojave and iOS 12 on an iPhone X. I used the phone with the mac for many minutes, then closed the lid (sleeping the machine) and re-opened it a few minutes later, and that's when the message appeared (the first one). I similarly found the popup to be suspicious.

It seems Apple has some bugs in their MobileDeviceUpdater software that cause this message to pop up spuriously.

This is happening to me with a MacBook Pro running High Sierra 10.13.6 and an iPhone X and iPad Pro running iOS 12.1. Apple support have told me that the solution is to upgrade to macOS Mojave, but I don't want to upgrade my entire OS at the moment. The error only occurs sporadically for me. Other people have reported that trying a different Lightning cable might work, or that the error only occurs when the phone is below a certain level of battery charge.