It seems you're looking for information regarding a file called "Facebook 4.0 iPhone IPA download." However, I must provide an important clarification and caution.
If you are interested in app history or nostalgia, consider looking up screenshots or videos of Facebook 4.0, but avoid attempting to install the IPA file. facebook 4.0 iphone ipa download
Facebook 4.0 was a major redesign released around 2013–2014. It introduced a faster interface, better navigation, and improved messaging. Today, this version is obsolete and no longer supported by Facebook’s servers. Even if you installed it, it would not work properly because modern Facebook APIs require much newer app versions. It seems you're looking for information regarding a