Sometime last week (I think) – ClickBank introduced IPN version 2.0 which is slightly different from IPN version 1.0.
The only details I could find was a blog comment here:
ClickBank IPN version 2.0 which was posted on 22nd September 2010.
So it’s possible that version 2.0 of the ClickBank’s Instant Notification Service (IPN) was introduced before that date.
If you are using any scripts that uses IPN – please make sure you select “version 1.0” in your ClickBank account.
I’ll be updating the codes to support version 2.0 soon and will keep you updated.