Apple ipod

Is it possible to upgrade a jailbroken iPhone to Apple iOS4 again?

I was wondering if it is possible to upgrade a jailbroken iPhone in Apple iOS4 again? By Apple, the new version iOS4 tomorrow (June 21, 2010). This will allow iPhone users to switch to the new IOS that has new features. But iTunes will update the version will take place or is there some type of procedure iPhone must be jailbroken to do this? iPhone is jailbroken version 3.1.3 has been saved with the sh before the flight software.

If you upgrade, you will lose the jailbreak and if you were using according to unlock jailbreak you'll lose. It was only a tool to jailbreak to be released in April for the operating system and if served by jailbreak unlock, hold your horses. iTunes is Always updated, but always a Jailbreakers barrier to prevent escape until released appropriate.

Steve Jobs launches IPhone 4 WWDC June 2010