From Sonic Retro
August 31 (
- 2003 — "Natsuyasumi Chao: Na Kansatsu Nikki", the 22nd episode of Sonic X, airs in Japan.
- 2011 — Issue #228 of the Sonic the Hedgehog comic series by Archie Comics is released in North America.
- 2016 — Issue #89 of Sonic Universe and issue #17 of Sonic Super Digest are released in North America.
- 2020 — Sonic the Hedgehog 2: Dr. Eggman no Unmei, a trade paperback, is released in Japan.
- 2021 — Sonic 30th Anniversary Symphony (Live) is made available to download from Amazon, iTunes, and the Mora, LINE, KKBox, AWA, and RecoChoku streaming platforms in Japan while it is released for Amazon, iTunes, YouTube Music, and Spotify worldwide.