SELECTEDVALUE() function not recognized

I'm trying to create a measure that grabs last year's sales so that I can compare them to this year's sales.

It is saying that the SELECTEDVALUE() is not recognized.

"The report measure FactSalesOrderDetail[Previous Yr Sales] has a syntax or semantic error at line 4, position 36, reported by Analysis Services: 'Failed to resolve name 'SELECTEDVALUE'.  It is not a valid table or function name.

Previous Yr Sales = CALCULATE(
	SUM(FactSalesOrderDetail[InvoiceQuantity]),
	FILTER(ALL(ActualDeliveryDate),
		ActualDeliveryDate[FiscalYear] = SELECTEDVALUE(ActualDeliveryDate[FiscalYear]) - 1 
		)
		)

Has anyone encountered this before?