To answer your question, you must update to the newest iOS (if you don't have blobs) or whatever Apple is still signing. The newest iOS came out yesterday, 5.1.1.. Also Apple quit signing 5.0 a while ago
No!
If you are on iOS 5.0.1 and wish to jail break, do NOT upgrade to the new firmware version (5.1.1). DO NOT!
As of this writing, we do not know if the new firmware fixes any exploits being used to develop a jail break for iOS 5.1. Until a jail break is released or until you are told to upgrade - by a respected/known member of the jail break community - the only action you want to do when a new firmware version is released is nothing!
And, mrMedo_90: If you are on 4.3.3, then the only way to keep your jail break is to stay where you are. However, if you want to upgrade and then wait for a jail break, then upgrade to iOS 5.0.1 NOW. You must do the upgrade within the next few hours before Apple closes the window for 5.0.1. Once that window is closed, you will have missed your chance and will not be able to go to 5.0.1.
If you choose to move up, download the 5.0.1 IPSW from here (make sure it's the right one for your device): http://www.ipadforums.net/showthread.php?t=24939
But, if you are going to do it, t'wer best done now. That signing window for 5.0.1 is closing fast. So, you have a few hours to decide whether to give up a jail break on 4.3.3 and move to iOS 5.0.1 in order to wait for a jail break - or keep waiting. Regardless, that window will close soon...
Marilyn