In the mid-2000s, Facebook did not exist as an application. It was a directory for college students accessed via desktop browsers. When the smartphone revolution began with the iPhone in 2007 and the T-Mobile G1 (Android) in 2008, Facebook’s mobile presence was initially a "wrapper." The earliest APKs were essentially simplified browser windows that loaded the mobile version of the website (facebook.com).
The true "1.0" era was defined by a massive technical struggle. Mark Zuckerberg famously stated that the company’s biggest mistake was betting too much on HTML5 instead of native code. facebook 1.0 apk