Android 4.4.2 is largely obsolete, with Google having dropped support for it in 2023. Upgrading to 9.0 offers:
If you meant you want to write an (e.g., for a computer science course) about legacy Android upgrades, let me know and I can provide an abstract, methodology section, and references on custom ROM development. upgrade android 4.4.2 to 9.0
Go to (or Software Update ). Tap Check for Updates . Android 4
Android 9.0 has a built-in RAM bar in Recents. Keep free RAM above 300MB. Uninstall heavy launchers (Nova Launcher Prime is fine, but avoid Lawnchair v2). Tap Check for Updates
Upgrading from Android 4.4.2 to 9.0 is technically possible only via custom ROMs but carries significant risk of instability and loss of features. Suitable for advanced users only. For most users, upgrading the device hardware is recommended.