Why does these commands are different inputs?

b box

They are different versions of the same component idea. The old component (with 3 inputs) was replaced by a component with only two inputs and a menu option on the component itself which replaces the third input.

so can i use this new one directly in place of old? or there is any setting to be done to get the result which we got from old one?

Try it, it should work fine.
You might need to right click on the middle of the component to select the option to “Union box”.