[Unity5]Button.interactable seems removed at Unity5, how to change it?

How to change interactable in Unity5?

@taxvi Unity 5 is available in a closed beta. The beta is available to customers who have pre ordered 5, and to subscription customers.

@peroon You might be better off with checking in on the forums, in the beta section. There are not a lot of experienced 5 users on answers yet.