Go into google and search Samsunf SmartSwitch. Then download it into your laptop or desktop. Plug in your device and back it up before hand just incase u lose anything ( nothing will happen but just to make sure). From there just download the software update it gives u.
It's better but you need to take advantage of doze mode. In addition, if you blocked most app notifications in lollipop (and you should to squeeze out more battery life) then you would need to do it all over again.
For doze mode go to the battery settings, select battery usage and under the "more" button select optimize.
Note that in marshmallow doze mode is active only when the phone is lying flat. It won't activate if it's moving in a pocket or bag.