While newer versions of iTunes (and eventually the standalone app on Windows) shifted focus exclusively to media like music and movies, many users still rely on version 12.6.3.6 for specific management tasks:

This is the biggest use case. Imagine you paid for Flappy Bird , Infinity Blade , or a specific old version of Facebook that works on an iPhone 4S running iOS 9. Apple removed those apps from the App Store years ago. If you have the .IPA file saved from iTunes 12.6.3.6, you can reinstall it forever. Without this version, you cannot.

In the rapid cycle of software updates, few versions achieve the status of a "cult classic." Usually, users clamor for the latest release—the shiny new interface, the extra features, the security patches. But in the world of Apple’s legacy media management software, there is one specific version that stands apart from the rest: .

However, with the release of macOS Catalina (10.15) in 2019, Apple famously "killed" iTunes. It split the monolithic application into three separate apps: Apple Music, Apple TV, and Apple Podcasts. The file management duties were handed over to the Finder.

it to something like iTunes Library.old to prevent conflicts.