: The latest major release is often cited as v8.5.0.0 , which was an AppX package.

: Version v11.0.1.0 (XAP/APPX) and v1510.7.114.0 (XAP) are common legacy versions found in archives.

A file (e-Xtensible Application Packaging) is the standard installation package for Windows Phone 8 and 8.1. For newer devices running Windows 10 Mobile, the format transitioned to APPX or APPXBUNDLE . These files act like offline installers, similar to an APK on Android, allowing you to bypass the defunct Microsoft Store. Latest Available Versions for Mobile

This is the most reliable method for both Windows Phone 8.1 and Windows 10 Mobile. Facebook 8.1 - Download XAP/APPX for Windows Phone

Installing these files requires "Developer Mode" to be enabled on your device to allow sideloading from external sources. Method 1: PC-Based Deployment (Recommended)