FortiOS 5.4 NSE4-5.4 is the older version named Fortinet Network Security Expert 4 Written Exam of the NSE4 exam and another one is Fortinet NSE4 Exam—FortiOS 5.6 exam. Pass one of two exams as you need is ok. Most of NSE 4 Network Security Professional exam candidates prefer to select FortiOS 5.4 NSE4-5.4 exam test.