A new version of the Windows Azure AppFabric SDK V1.0 is available for download starting 10/27. The new version introduces a fix to an issue which causes the SDK to rollback on 64 bit Windows Server machines with BizTalk Server installed.
The fix is included in the updated SDK download. If you are not experiencing this issue, there is no need to download the new version of the SDK.
The Windows Azure AppFabric Team