Your recovery is checking for the wrong device model. Fix: Open the ROM zip on your PC, navigate to META-INF/com/google/android/ and delete the assert lines in the updater-script file, or install a custom recovery.

You can download official firmware from sites like SamMobile and flash it using the Odin tool on a PC.

If the OTA check fails, your next best option is to use a PC to "flash" the official update. This is the safest method because it uses software signed by the manufacturer.

Updating a device from Android 4.4.2 (KitKat) to 5.0 (Lollipop) depends entirely on whether your specific manufacturer released an official update for your model. Because Android 4.4.2 was released in 2013 and official support for Lollipop ended years ago, modern automated downloads are no longer active for most devices.

: Swipe down from the top and tap the gear icon.

This voids your warranty (though you likely have none) and requires technical skill.

Since you will likely sideload the update: Go to Settings > Security > Unknown Sources → .