iOS User Agent String will be frozen for the OS part to 18_6.

[karlcow]

What is the issue with the Compatibility Standard?

For example:

Mozilla/5.0 (iPhone; CPU iPhone OS 18_6 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.0 Mobile/15E148 Safari/604.1

As you can see: OS 18_6
It will not be switched to 26.

[janbrasna]

What is the best timing to note that in https://compat.spec.whatwg.org/#ua-string-tokens-safari as a constant, usually?

[karlcow]

Probably when the version 26 of the OS is being released.

[miketaylr]

Thanks for the heads up.

[janbrasna]

So it only will be really frozen in iOS 26 proper, not in iOS 18 already through further updates, OK. Therefore with existing iPhone OS 18_6_1 and iPhone OS 18_6_2, and in case iOS 18.6.x releases some security patch versions over time, these would continue to follow their implicit iPhone OS 18_6_3, iPhone OS 18_6_4 etc., so such values are still expected too, over time?

(Just figuring out what the expectations should be, if this is documented as a constant of iPhone OS 18_6, in case it's only 100% valid for the latest major OS.)

[karlcow]

This is still being discussed. Stay tuned.

[janbrasna]

And, alas, this has been moved to 18_6_2 and later to 18_7 — with 18.7.1 just released this might be a moving target for a while.

https://bugs.webkit.org/show_bug.cgi?id=298473

• Revise frozen Safari UA iOS version to match actual last-shipped iOS version WebKit/WebKit#50383

https://bugs.webkit.org/show_bug.cgi?id=298673

• Update frozen iOS version to 18.7 to match new SU RC WebKit/WebKit#50559