From the FAQ, here are some details:
From February 1, 2009 through January 15, 2010, Softimge XSI customers will have the option to migrate their existing products to the then current Autodesk Softimage products at 50% off SRP when purchased with Autodesk Subscription.
All migration purchases will be fulfilled with Autodesk network products. If standalone licenses are desired, a request to downgrade to standalone licenses should be noted on the order.
When you use the -processing flag, you can ignore the “Unknown flag” warning. As long as you see “License information: using [Processing]”, you know that xsibatch is using one of the unlimited processing licenses.
C:\Softimage\Softimage_2010_x64\Application\bin>xsibatch -processing-script hello.js
Autodesk Softimage 188.8.131.52
License information: using [Processing]
COMMAND: -processing -script hello.js
WARNING - Unknown flag (ignored) : -processing
# INFO : Hello World