Board Thread:General Discussion/@comment-18053181-20141214100556/@comment-100.32.240.163-20150211112201

In this case, I think I have an easy way of explaining this: The "reboot" portion is more of a combined modern patch-up and filler. When it comes to the overall stated retcons, the ones initially stated in the core series are how Kirito recalls them. The changes made in Progressive are the actual events.

As in the core focus of the main series is Kirito. This means that the core series explains how Kirito remembers the events. And with the Progressive series, the main focus is both on Kirito and Asuna. So atop of Asuna's experiences being explained, the reader get to know what actually did happen from the beginning.

Also, when it comes to the making of the series, Reki Kawahara did give two explanations: The first being that he wanted to give the series a modern reboot. And he said that an MMO that does not receive an upgrade is a sad one. The other was stated at another point, and he stated that he did not want to make the Aincrad arc feel complete until he had both the time and ideas to make it the way he has imagined it to be.

So you were half-right when it comes to the definition. But when it comes to the series itself, it is 100% canon and helps Reki Kawahara feel like he has given the fanbase an overall complete experience when it comes to Aincrad.