Payroll hell and damnation
Our company doesn't do payroll, even though there's a venerable army of HR and Finance people. Who the @£$% knows what they all do all day. When you approach them with a question, they tell you to contact ADP. So you do and you're told "our app only works with IE 10". Not 11, not 9, not even Edge -- IE 10.
Thus if you need to know what's on your payslop, or what deductions, or G*d forbid your end of year PAYE info, you have to run IE 11 in IE 10 "bassackwards compatibilty mode" or you're blocked from even logging onto their site.
Don't even think about Firefox, Safari or Chrome "unsupposed and insecure" is the message from ADP regarding them.