Go to Settings > Applications and check the box for Unknown Sources . This allows you to install apps from outside the Play Store.
Only use reputable sites like APKMirror or OldVersion.com. Avoid unverified blogs to protect your device from malware. How to Install the App download facebook app for android 2.1
Since the official Play Store no longer supports Eclair for the Facebook app, you will need to use a trusted APK archive. Go to Settings > Applications and check the
Android 2.1 Eclair was released in early 2010. Because the current Facebook app is built using modern APIs and security protocols, the version found on the Google Play Store today will not install on such an old operating system. Avoid unverified blogs to protect your device from malware
💡 Many older apps use outdated login protocols. If you get a "Connection Error," it is likely because Facebook has retired the servers that version tries to talk to.