Legacy operating systems lack modern cryptographic protocols. Android 4.1.2 does not inherently support Transport Layer Security (TLS) 1.2 or 1.3, which are standard for securing internet traffic today. Running social media apps on unpatched software exposes your login credentials and personal data to interception on public networks. Risks of Third-Party APK Websites
To understand why installing a Facebook APK on Android 4.1.2 is difficult, it helps to understand how software architecture changes over time. API Level 16 Limitations facebook apk android 412 exclusive