Error messages · Chrome extension

'webRequestBlocking' requires manifest version of 2 or lower

What you see

'webRequestBlocking' requires manifest version of 2 or lower.

Why it happens

The code blocks or changes web requests with chrome.webRequest and "blocking". Version 3 extensions installed from the store can’t do that: Chrome only allows "webRequestBlocking" up to version 2. Blocking now uses declarativeNetRequest rules, which work differently, so this can’t be renamed.

The fix

• rightsocket does this Takes "webRequestBlocking" out of the manifest so this message goes away, and marks the blocking code Check, so you know before you install it.
• You do this Ask ChatGPT to rewrite the blocking part with chrome.declarativeNetRequest rules for Manifest V3, then paste the new code here.

What changed, and when

• 24 July 2025, Chrome: Chrome 138: Manifest V2 extensions disabled for all users on all channels, with no option to turn them back on. Chrome 139 then removed the enterprise policy that kept them working.

Sources

• Chromium source: permissions limited to version 2 (_permission_features.json)
• Chrome for Developers: chrome.declarativeNetRequest
• Stack Overflow: "'webRequestBlocking' requires manifest version of 2 or lower"

Other chrome extension errors

• Manifest version 2 is deprecated
• Service worker registration failed. Status code: 15
• Manifest is not valid JSON
• Could not load icon specified in the manifest
• Refused to execute inline script (Content Security Policy)
• chrome.browserAction is undefined (Manifest V3)
• 'browser_action' requires manifest version of 2 or lower
• Permission is unknown or URL pattern is malformed
• Invalid value for 'web_accessible_resources[0]'
• Invalid value for 'content_security_policy'
• Insecure CSP value in directive 'script-src'