i integrating facebook ios sdk 4.0 in mobile app. came scenario user logged our mobile app facebook credentials, after time user changed password , firstname in facebook. how track change in mobile app? , redirect user validate facebook credentials in mobile app?
in both v3 , v4 of sdk, access token cached locally on device (by default), , way know if it's still "valid" make graph request.
you can make /me or /permissions request during app start if have cached token, , check errors, , prompt user re-log in if token no longer valid. there auto-error recovery mechanisms built sdk, see https://developers.facebook.com/docs/ios/errors.
