We are testing 'restore subscription' using Apple's new in-app subscription model. The In App Purchase Programming Guide lists 6 status codes that are returned by the Apple server during the restoration/purchase process ("Verifying an Auto-renewable receipt" - page 33/34). However, the errors start at 21000 and end at 21006. We just tried to restore a subscription and received a status result of 21007. I have googled this error and am not finding any information about what this status result means. Thank you in advance ....
Error 21008 is also another Error response that Apple returns if you point to the wrong production/sandbox server.
Do not point your script to the live Apple server when you're testing using the sandbox(!)
Lesson learned. Hope this post helps someone else.