Google Stopped its Referral Service

As other Adsense publishers, I have received a message from Adsense support telling me the the referral service will be stopped, and any referral units should be removed of altered by Adsense for content units.

You can use Adsense for content ad units instead of the current referral units, but you must already have less than three Adsense for content units "the maximum number". Or you can join the affiliate network that is provided by Google, but it is not provided for all countries.

Don't worry, they just need to improve their services and I have to thank them all the time.