Jailbroken iphone update to ios7

Hi ppl. I have two questions.I have a jailbroken iphone 4 with ios 6.
1. I have not yet received the update of ios 7. I check in general>software update =no update. and in itunes am receiving update ios 6.1.3.

2. If ever i got the update, i want to update my iphone to ios 7 and i dont want to jailbreak it. How i do i proceed?
coz i read online, they said jailbroken device should backup ssh and it's not safe to update to ios7. Please Advice me and clear my doubts.

Thanks in Advance