Board Thread:S,R,&G/@comment-3014077-20170613144725/@comment-29759785-20170613154515

I think that at this point we cannot make final decision about OS, whether it's non-canon or retcon to canon. The movie, initially, was set after Alicization arc, but it was changed due to Directior's suggestion. As you mentioned, Reki himself is not sure what to do. In one of his recent answers on twitter, he said that he still needs to figure it out and it depends whether he will write novelization of Ordinal Scale.

I would vote for putting OS into grey area (kind of pending status). Not confirmed to be canon, but at the same time with the possibility of being one.

The main differnce between OS and Progressive series, is the that former gives us major contradiction (or "possible" retcon) to the whole choronolgy, which is putting one arc before or after another. Progressive, on the other hand, retcons only minor things, which are easy to accept and don't pose big contradictions.

To sum up, in my opnion, it is safe to put on hold any deep delibarations untill we know more.

Who knows, maybe in new, upcoming arc we will find some answers - tightly keeping his fingers crossed for appearence of the ring.