We've learned that Apple has released Beta 6 of the Apple Software Development Kit, and the new build labeled 9m2192 comes with an updated firmware - build 5a308. It has been noted by some sources on the Internet that SDK Beta 6 also institutes a new system of provisioning, and it is tied closely with Application IDs.

That said, registered Application IDs are a requirement prior to installing the appropriate software on your iPhone, and developers are now required to make Application IDs for their own software. Also, third-party developed software profiles will have to be upgraded to be compatible with the latest provisioning system.

Mac OS X Leopard 10.5.3, released prior to SDK Beta 6, is also a requirement to using the latest SDK beta release, and it was reported that users will now be able to log into the developer's portal (Apple Dev Center - reachable via the source link below) in order to download the 1.2 GB-heavy archive.