Updating the Jailbreak from Os 6 to 7

Hi,

I have Iphone 4S which is Jailbroken and I'm using a sim tray also for using mobile network.

Currently it is having OS 6.0.1 and i want to update it to the latest OS 7 through Jailbreak.

Can anybody advice on this if they have done that and also wanted to confirm that after updating it will keep supporting the sim tray that i'm using.

Thanks in Advance.

Regards,
Shaan