Ready to file my first T2. Fiscal year end July 31, 2017 - am I using a 2016 or 2017 version of the T2? In general, is your "filing year" based on fiscal start or end?

I know this seems like a Corporate Tax 101 question, but believe it or not, nowhere on any site (including CRA) can I find which "tax year" form to choose.  So, for anyone with a non-calendar year end, and therefore the fiscal year covers two different calendar years, do I want to use the form that corresponds with the year my fiscal began in, or ended in?