migration-guide

To migrate a Chrome extension from Manifest V2 to Manifest V3, update the manifest_version field to 3, replace background scripts with a service worker, adapt permissions and content scripts, and configure declarativeNetRequest rules.

Background pages are replaced by service workers in Manifest V3 to handle extension events. You must register the service worker in the manifest and adapt your background scripts to manage state persistence without DOM access.

Migrating webRequest blocking to declarativeNetRequest in Manifest V3 involves defining static or dynamic rules in JSON format and declaring the declarativeNetRequest permission instead of using imperative webRequest interceptors.

Yes, upgrading to Manifest V3 requires removing remote code. You must bundle all logic locally and update executeScript calls to inject static files or strings rather than loading external scripts dynamically.

Persistence strategies for Manifest V3 service workers involve using chrome.storage and alarms APIs to manage state, because service workers are ephemeral and terminate when idle, unlike persistent background pages.

Updating the manifest_version to 3 breaks Chrome extensions because MV3 introduces architectural changes, requiring background page to service worker migration, host_permissions separation, and declarativeNetRequest API adoption.