Upgrade Dawn Theme from Version 9 to version 10 and keep custom coding

Hi There

i added some customer coding that i added to the dawn them (from This forum)

and i see there is a new version, and i want to make sure that the codes i have on version be added to the new version , i know some of the codes ( i save them on note pad) but some i forgot where i put them

i want to know if there is a sophisticate way i can keep all my custom coding

Thank You