Apple’s security model requires apps to be "signed" by a valid certificate to run. When you download an app from the App Store, it is signed by Apple. If you download an IPA from the web, you must sign it yourself using a tool like AltStore, Sideloadly, or Cydia Impactor.

Sometimes, updates introduce features that users actively dislike, or changes to privacy policies that make them uncomfortable. Rolling back to an old version is seen as a way to opt out of modern data tracking implementations or integrated features like "My AI" or the endless scrolling of the "Home" feed.

Facebook runs on server-side logic. Even if you install an IPA of Messenger version 50.0 from 2015, the Facebook servers may reject its API calls. You will likely see an error message: "Update your app to continue chatting." Facebook forces sunset dates for old protocols.

: Note that Messenger Lite has been discontinued for both iOS and Android and may no longer function even if the file is installed.

Old IPAs run buttery smooth on legacy hardware. For many users in emerging markets or those holding onto their "vintage" iPhones as daily drivers, the old IPA isn't a novelty—it's a necessity.

If you have a jailbroken iPhone, running an older version of Messenger allows you to use legacy tweaks (like Messenger++ or Watusi ) that haven't been updated to support the latest version.