Can I upgrade my iphone 3g from 3.1.2 to 3.1.3 now?

[bestlaw]

Sorry for my stupid question.
I'm afraid that Apple won't recognize 3.1.3 now and then force me to upgrade my iphone3g to firmware 4.1.
Is there any suggestion?
Thanks.

 

[Applejuiced]

Yes, you can go to 3.1.3
From 4.0 and higher is when software SHSH's came into play with iphone 3G models.