According to Wikipedia: "If the end of IDT falls on Rosh Hashana, then IDT will end on the first Monday after October 1."

Reading a little further:

On July 8, 2013, the Knesset approved the bill to extend IDT even further. According to the bill, IDT will begin on the Friday before the last Sunday of March, and end on the last Sunday of October.[14]

Huzzah, at last!