pub-123456 to ca-pub-123456

My adsense account is approved since 2008 and then my publisher ID was pub-123456. The same was given in the ad units as google_ad_client = "pub-123456". But very recently I have found that my publisher ID is still showing as pub-123456, but the ad codes inside the 'My Ads' section is showing google_ad_client = "ca-pub-123456" !!!
Now my ad units are spreaded across different webpages of multiple websites, which is very difficult to track back and change. If I leave those existing ad units as…
pub-123456 to ca-pub-123456

See original post by vola