If you are a current Object Desktop subscriber, you are able to run the pre-release versions of the software. To do this you need to turn on "show pre release versions" under preferences in Impulse by clicking on the blue button in the upper left corner of the program. Once you do this it should show in your updates tab.
It will show as DeskScapes version 2.92 beta in the file descriptions, not DeskScapes 3.
If you have a problem updating it try clicking on the "install all updates" button under the help icon.