Upgrading my jailbroken version

[Djflacolive]

When I first got my Iphone 4 I jail broke it and also unlocked it for T-Mobile, to this date I'm using version 4.0.1. I want to know if there's a newer version that I can update my phone to and be able to jailbreak/unlock my phone.

Please provide me with instructions if so.

[Orby]

When I first got my Iphone 4 I jail broke it and also unlocked it for T-Mobile, to this date I'm using version 4.0.1. I want to know if there's a newer version that I can update my phone to and be able to jailbreak/unlock my phone.

Please provide me with instructions if so.

You can go to 4.1, stay jailbroken (untethered), and unlocked if you know how to preserve your baseband (and have 4.1 SHSH blobs saved).

Easiest method to ensure nothing goes wrong is probably a custom IPSW from PwnageTool. If you don't have access to PwnageTool, I'll cook a custom firmware for you, all you'll have to do is put your i4 in pwned DFU with redsn0w and restore to it with iTunes.

[i.Annie]

With an iPhone 4, TinyUmbrella is probably the easiest route. All you do is run the TSS server while shift+restoring to 4.1 stock. Then jb with limera1n, greenpois0n, or redsn0w 0.9.6b6. Using a custom fw is fine but it has to be with PwnageTool. You'll also need SHSHs for 4.1 for both of these methods.

[Djflacolive]

I wanna make sure I do everything right the first time. Also, am I going to lose everything that I have on my phone like the apps, email, settings?
I have my laptop ready just please tell me what to download to upgrade my phone, or better yet some step by step instructions.