Bumping because according to a post on an Arthur Tumblr page, Netflix added Season 15...but removed Seasons 1-12.

Hulu has all of Seasons 7-14, and Amazon and iTunes have 10-15. Looks like anything before S7 can now only be viewed on YouTube outside of TV...

I liked how Netflix used the versions that air on PBS now, minus the funding credits. This meant that Season 1 episodes had the episode titles read aloud and Season 6 had Arthur's voice redubbed (I believe "Sue Ellen Gets Her Goose Cooked" and "Best of the Nest" are the only episodes who have their redubbed versions on YouTube. Every other Season 6 episode, including other uploads of those two, have the original Arthur voice), though it also meant that Seasons 12-14 (and now 15) were not HD (are there any S12 uploads on YT that are the HD versions? I don't recall seeing any, but apparently that's when HD production started).

And I liked the original "And Now a Word From Us Kids" sting used in original/non U.S. broadcasts of Season 1, which has since been redubbed with a later version. I think you can still hear the original sting in YT uploads of "Arthur's Eyes/Francine's Bad Hair Day" since other countries use the original episodes and PBS often has to make modifications to them for newer funding credits and PBS promos.