Well atleast I hope, thats what I heard from alot of people and That is my good guess because they probably do that because they did that to gold & silver
You can trade with the old games but you can't trade new pokemon or have new items while trading and having attacks that are not in the old games like gold & silver trading with yellow,blue or red.
sorry, beein trying to find this file that's been right in front of me for a month now, only to find broken links, and google to prove that it's completely worthless.