If UDP communication is used to obtain NTP, will it be approved by the Apple Store review?

Question

Created Apr ’25

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There may be mistakes in the English translation. Please understand.

I am developing a smartphone application using Unity and considering using a public NTP server to obtain the current time.

During my research, I found an article stating that communications using UDP are blocked by Apple's review process. The article also mentioned that obtaining the time via HTTPS communication successfully passed Apple's review.

If an app uses UDP communication to obtain the current time from NTP, will it fail the review process?

When I built the app in Xcode and launched it, the current time obtained from NTP was displayed in the Xcode log, so I believe the communication is working properly.

Below is the URL of the article I found.

https://deep-verdure.hatenablog.com/entry/2020/05/06/050506

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Answer 1

DTS Engineer OP

Apple

Apr ’25

Recommended

I don’t work for App Review and can’t make definitive statements about their policy or review setup. However, my experience is that:

App Store apps are allowed to use UDP, as witnessed by the bazillion apps in the store that do that.
There are many real world networks that provider HTTP access to the wider Internet but block UDP from doing the same [1]. If you build an app that uses a UDP protocol, it’s a good idea to have some sort of fallback mechanism so that your app works on such networks.

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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

[1] The most obvious example of this is a network where the only access to the wider Internet is via an HTTP proxy.

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Answer 2

App Review OP

Apple

Apr ’25

Thank you for your post. We recommend that you sign up for a session with App Review during the weekly Meet with Apple event. Sign in with your Developer ID and select "Request a one-on-one App Review consultation". A member of the App Review team will help you with your questions regarding the review process and the App Review Guidelines.

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