A history of, plus mention of an interesting incident in 1994:
In 1994, with the codex in hand and books of the Prophets intact, Yitzchaki, with the help of a scribe, printed a new addition of the Prophets. Rabbi Avraham Yitzchok Hoffman, an American-born haredi residing in Mea She'arim, was outraged. He claims that changing even one letter of the canonized text is heresy. Hoffman galvanized haredi leaders to condemn Yitzchaki and he plastered broadsides throughout Jerusalem denouncing the publication and its editor.
Yitzchaki claims that although Hoffman lives in Mea She'arim he does not speak ex cathedra and, he asserts, Hoffman had misled rabbinic leaders about the importance of the codex. "When I explain to these rabbis the context in which the codex was created, they back down and even support my work," says Yitzchaki.
Hoffman disparagingly refers to the Aleppo Codex as a "new archaeological find" and insists that Jews must adhere to the 13 principles of faith as dictated by Maimonides. He is referring specifically to the eighth principle, commonly understood to mean that every letter and dot, no matter how small, is of Divine origin. Indeed, in Orthodox synagogues, if a reader of the Torah makes the most minor of mistakes (which is easy to do since Torah scrolls contain no vowels), the congregants shout the correct version at him until he reads it correctly.
The irony is that Maimonides himself gave currency to the codex. It is, in fact, the Bible of today that differs from Maimonides' edition a millennium ago.
Although there exist various biblical codices containing textual variations, Orthodox Jews are typically exposed to only one unified text. The reason is simple: with the invention of movable type in the 15th century, printed Bibles became uniform.