[Toolip] attribute and older versions of unity editor

I'm writing an asset for the unity asset store. I'd like to use the new "tooltip" attribute. However I'm aware it doesnt work in older versions of the editor. I could do this...

 #if UNITY_4_5
 [Tooltip("flippy floopy flop")]  
 #endif
 public float Flupo;

But then the tooltips will only show up in version 4.5 and not future versions of unity. Is there a way to check for a certain version of unity editor or any newer than that?