Iphone 4s JailBroken Jv Sim. Need To update to IOS7?

I have a iphone 4s jv sim. Its jailbroken and i want to update it to ios 7. My current version is ios 5.Is there any risk i need to know or should i update it no worry?
Need some Help.

I would restore the iPhone in iTunes before updating the iPhone to latest iOS. However I would leave the iPhone running with the current iOS even though you can't buy new apps direct on the device which require iOS 6 or higher.

Few reasons why you shouldn't update: http://ipod.about.com/od/UsingiOS7/fl/Should-I-Upgrade-an-iPhone-4-to-iOS-7.htm

Don't upgrade jv sim will not be used.