demo ยท v139

OS Version Compatibility Detector

ChromeStatus says Chrome 138 is the last release to support macOS 11 Big Sur; Chrome 139+ no longer supports it, and new Chrome 139+ installs require macOS 12 or later. This demo reads User-Agent Client Hints when available, then lets you drive every branch your site needs for supported, unsupported, missing, and malformed OS signals.

detector input

Change any field to re-run the classifier. The missing-hint branch intentionally avoids trusting the reduced user-agent string as a precise macOS version.

waiting

Choose a detector input

Use a scenario, enter custom values, or detect this browser.

source manual scenario
decision branch not run
platform macOS
platformVersion 11.7.10
Chrome major 138
hint state available
The visitor-facing message appears here.

support timeline branch

OS signal Chrome support branch Site response

headers and replacement pattern

A production site should request the high-entropy platform version, classify only after the hint arrives, and show a targeted upgrade message for macOS 11 visitors.

res.setHeader("Accept-CH", "Sec-CH-UA-Platform, Sec-CH-UA-Platform-Version");
res.setHeader("Critical-CH", "Sec-CH-UA-Platform-Version");

const platform = req.get("sec-ch-ua-platform")?.replace(/"/g, "");
const version = req.get("sec-ch-ua-platform-version")?.replace(/"/g, "");
const major = Number.parseInt(version, 10);

if (platform === "macOS" && major === 11) {
  res.locals.showMacOs11Warning = true;
}

see also