If you do your accounts on an accrual basis then it appears in the year when it becomes a receivable [year to 31-Mar-17].
However if you do your accounts on a cash basis it appears in the year it is received [year to 31-Mar-18].

couta1 is making an assumption which may be valid but, I assume, probably is not.

waikare is possibly confused now.

Best Wishes
Paper Tiger