Android upgrade?

So, I picked up an old ASUS memo pad 10 (found it on Yahoo!) that’s running Android 4.2.2 right out of the box. Since the thing is about five years old now, I figured I’d try to bump it up to a newer version of Android, but I'm hitting a wall here.
I went through settings/about/system update and hit check update.
But then this message pops up: "internet connection error or the server is busy". I've been messing with it all day and nothing is working.
Anyone have any clue what's actually going on?

Even if it wasn't ten years old, Android 4 is ancient history at this point. I'm pretty sure there isn't an official update coming, so you might be able to find some custom ROMs, but that's going to take a bit of work.

There's a firmware update sitting right here. I'm just not entirely certain if this covers the Android OS as well.

https://www.asus.com/us/supportonly/...HelpDesk_BIOS/