css.properties.dynamic-range-limit - Requires macOS 26 or iOS 26 in addition to Safari 26

[lapcat]

What type of issue is this?

Incorrect support data (example: BrowserX says "86" but support was added in "40")

What information was incorrect, unhelpful, or incomplete?

Safari support for dynamic-range-limit

What browsers does this problem apply to, if applicable?

Safari

What did you expect to see?

macOS 26 and iOS 26

Did you test this? If so, how?

I checked the Safari web inspector on macOS 15 Sequoia and macOS 26 Tahoe.

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

"This requires system-level support, so macOS 26 and iOS 26." w3c/csswg-drafts#11711 (comment)

Do you have anything more you want to share?

No response

MDN URL

https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Properties/dynamic-range-limit

MDN metadata

MDN page report details

• Query: css.properties.dynamic-range-limit
• Report started: 2026-02-18T23:20:04.786Z

[caugner]

We should definitely add a note explaining this requirement, e.g. "Requires macOS/iOS 26 or later.".

Operating system limitations imply partial_implementation, but this rule was made for browsers that are available on more than one operating system, not for multiple versions of the same operating system.

Nevertheless, @ddbeck's comment in a recent PR makes me think marking the feature as partial is the right call for now. However, assuming this feature will never be available in earlier macOS/iOS versions, this implies the feature will only be unmarked as partial when a Safari release comes out that requires macOS/iOS 26 or later. (This is an interesting case to bear in mind for #27364.)

[ddbeck]

What's the actual behavior if you're outside the requirements here? e.g., does CSS.supports("dynamic-range-limit: standard") return true or false on macOS 15?

[lapcat]

What's the actual behavior if you're outside the requirements here? e.g., does CSS.supports("dynamic-range-limit: standard") return true or false on macOS 15?

false

[ddbeck]

I think we should use a note without a partial here.

IIRC, macOS 15 doesn't have HDR support in any case. I think this specific situation is more in the spirit of the second guideline:

However, this guideline does not apply to features where the browser's expected behavior is conditional on the behavior of the operating system itself. For example, a browser can fully implement a CSS media query even if an underlying operating system can never satisfy the media query's condition because it does not support the requisite hardware.

But even if that weren't the case, our OS limitations guideline was more our answer to the difficulty of trying to retrofit something like chrome_windows, chrome_macos, etc. to represent different OS platforms' support. It'd be kind of absurd to represent the whole matrix of OS, OS version, and browser version in our schema.

Perhaps we could amend our guidelines to say that we presume, for the purposes of setting partial_implementation, that it's presumed that the browser is running on the current release of the operating system in question (and to note other OS release differences on best-effort basis).