401k 5500 filing question

If the 401k plan year is July 31, 2018 to July 31, 2019, do you use the 2018 or 2019 5500 form?  

Thank you.

2018.

Thank you very much for the reply.

For 5500 Series purposes, always use the year of the plan year beginning date.

I agree, you use the form that matches the beginning of the plan year, but in this case, I'm not sure the plan year is correct.  Does the plan year begin on July 31 or does it end of July 31? Is the question about the 8/1/2017 to 7/31/2018 (2017 5500) or is it 8/1/2018 to 7/31/2019 (2018 5500)?