Books belong in series?

[David]

Per previous discussion I create Silo Saga Universe series to distinguish it from Silo series. So this question is not about that.

My question is about the other books added to the Silo series:
Greatfall: The Complete Novel, The Silo Archipelago, Silo Submerged, WOOL Gathering and definitely The Sky Used to be Blue. To me they don't seem to belong. Even if the author is somehow aware of them ("endorsed by", "encouraged by"), I think they are far from being canon. They are books created by other authors in the same universe, outside the Kindle Worlds so they don't even belong to that.

There seem to be some librarians fighting over them back and forth.

[Krazykiwi]

Hugh Howey is pretty approachable.

I'm normally very leery about approaching authors, but in this case, it might be your best bet to just ask him which books are canon/the original series, and put a stop to the back and forth'ing.

(ETA: Fix dumb (really dumb) thinko in author's name.)

[David]

Ok, I left Hugh Howey a message.
(I am actually surprised with how attentive authors are in GR, I just got some very quick responses to other queries I made with authors)