This check reports browser features marked as deprecated in the current runtime. A warning may originate from first-party code, a dependency, an extension, or an embedded third-party script.
Why this matters
Deprecated APIs can stop working in a future browser release, create security or privacy concerns, and block modernization. The console warning alone does not identify ownership, so trace the call before changing code.
How to fix it
- Use the warning’s stack trace or initiator information to locate the script and call site.
- Check current browser documentation for the recommended replacement and compatibility requirements.
- Upgrade or replace the owning dependency when the call is not in first-party code.
- Avoid suppressing the warning without removing the deprecated behavior.
When the finding appears across many URLs, fix the shared component or layout that produces it instead of patching generated HTML page by page. Recheck representative templates and responsive states after deployment so the correction does not create a regression elsewhere.
How to verify the fix
Exercise the interaction that previously triggered the warning in supported browsers. Confirm the console is clean and that the replacement preserves permissions, error handling, and user-visible behavior.
Keep before-and-after evidence for the affected URL, original output, correction, and verification method. If markup changes after load, test consent states, localization, responsive variants, and client-side navigation because the initial HTML and rendered DOM can differ.