I found some people confuse about Network+ JK-code and N10-004,N10-005,here is a simple explanation: The JK code sequence is for the Japanese/Korean/Chinese language version of the exam. The N- code sequence is the English language version N10-004 was the version of the exam released in 2009 N10-005 was the version of the exam released in 2011 The two exams ran concurrently (you could chose which to do) for approximately 12 months, but the N10-004 version was retired in mid-2012. The ONLY version of the exam that you can currently sit is the N10-005 version.