The program is set to expire on 9/30/17. When we approach this date, the government can either pass legislation to reform the program, which would likely include increasing the investment amount to at least $800,000, or they can pass another short-term extension to December. Or they can decide not to reauthorize the program altogether, which is extremely unlikely.
Given how slowly the government works, I have a hard to envisioning new legislation to be passed by September 30th. Therefore, it seems most likely that we will see another short-term extension like we've been experiencing for the past two years.