Originally Posted By: zmjezhd
it's not back-formed from postpone? I see on the other words board ..., Faldo has asked after prepone.


And it looks like I've gotten an answer. The estimable languagehat has proclaimed it to be from Indian English. It was seen earlier in American English but the source of the modern usage is Indian English. And if languagehat says it, I'm prepared (or even postpared) to believe it.