About New Apple iO 6 software

Hi,

I am using iphone 4S, Recently apple have launched new iphone 5, During the presentation they have shown all the new feauters in new phone and at the end they have informed as they are giving a free update to IO6 for all the users of iphone 4s, iphone 4....etc. If we make an update to IO6 from 5.0.1, does the battery backup will decrease from the present in iphone 4s or it will remains same?