How to jailbreak my iphone 4 with 1.6.3?

I have jailbroken in the past multiple times, but for some reason I can't do it anymore. I'm assuming that apple has patched something in the software so that jailbreaks are no longer possible… I have read forums saying that jailbreaks aren't possible on v 1.6.3. Can anyone help me Please?

Let me know if it is not possible, or if it is, could you possibly give me a link?

There's no such thing as 1.6.3 on an iphone 4. But if you mean 6.1.3 then no jailbreak. You can downgrade thought.google SHSH downgrade.

No jailbreak and you can't downgrade.