The show's logo contains text that uses a font called Generation B, as produced by Harold Lohner and it is available to purchase for $19.95 (20 US dollars).
Fans began to produce their own material (artwork/videos/websites/games/etc.) based upon the show and they thought it would be great if the text that appeared in their material could look like that in the show's logo.
As such, at some point in time, a replica image was produced and released onto an image board that contained more or less a trace of the text in the logo. This image was used by someone named Purple Tinker as a basis for the original Celestia Medium font.
Some people began to pick up on, and question the morality/legality behind working on a 'knock-off' of a commercial font, as a consequence work upon the original Celestia Medium stopped, as too did it's (regular) availability.
Mattyhex managed to track down a copy of Celestia Medium, and decided he'd work it into a less legally questionable 'fanbased' form. From the original font file, he exported each of the available glyphs as an SVG and reworked them in Inkscape (and also produced several new ones).
This allowed him to make the redux different from the original and also, hopefully, made it distinctive from Generation B.
Mattyhex asked Harold Lohner if he didn't want him to, he gave Mattyhex the very clear line of 'please don't rework the Generation B files', which he can't.
Below are two examples of the difference between the old Celestia Medium glyphs, and the new Redux version.
First is the glyph for 'R'. This particular glyph (and some others similar to it) is very distinctive, as such working it to look different wasn't easy.
It's worth noting here, that the differences on this scale are noticeable, however when shrunk to a much smaller scale, it's probably a difference of <1px.
Secondly is a glyph which Mattyhex made very different to the old Celestia Medium version, '9', again blue is the old version, above the new red one.
- v1.55: Minor fixes, new lower-case "k" and "m", otherwise very similar to the previous version. Also has a version that contains an alternative 'I', for people who don't want a dot above the capital.
- v1.5: Lower-case letters added.
- v1.35: Maintenance update.
- v1.3: Russian glyphs and more Greek glyphs added. A lower-case "o" was also added.
- v0.5: More symbols and accented capitals added. Kerning pairs for both "O"s.
- v0.4: All symbols were reworked.