He is going to tell everyone about the Obama's filing for divorce. Just like Bill and Hillary and many others, they will fake it for power.
That's what some people are saying due to a person close to Trump supposing.
If that happens to be all it is, then Trump just made a (bigger) fool of himself. I don't think that's it though... go look at Trump's twitter and he's saying it's going to be huge and leads everyone to believe that it's not old information. we've known about the Obama's having marital issues 8 years into their marriage with all the details for some time now.