The 6th edition of the PMBOK was released in Sept of 2017 (Sept 6, to be precise). Much of the content on this site dates back to that if not before however many of the concepts have remained the same (though the names may have been changed to confuse the unwary... *grin*) We will work to update key content in anticipation of the next release of the PMBOK, tentatively scheduled for 2020. That's a guess, mind you: The 2nd edition launched in 2000, 3rd edition in 2004, 4th edition in 2008, 5th edition in 2012, and 6th edition in 2017. Save for the last edition, that's every 4 years.
Holy Diapers! There's a lot of stuff in the PMP Exam this time around, and it only gets worse and worse, bigger and bigger each year.