Fly Tablet-no system upgrade button-how to upgrade?

[AC Question]

fly Tablet-no system upgrade button-how to upgrade?

I have fly f8s tablet which has jelly bean 4.1.
The specs of tablet are as follows
Key Features
8" (20.32 cm) XGA Display Screen
Android v4.1 Jelly Bean OS
1.2GHz Dual Core Processor
Dual Camera Rear - 3.2 MP / Front - 2 MP
3G & EDGE Connectivity
4000 mAh Battery

I want to upgrade it as one of my application which i need is not working.
But there is no system upgrade button in about tablet in settings.

I am new to android. I even restored it to factory settings still no button.

I can install custom os or do whatever is needed but i need to upgrade that to 4.2 or 4.4.
How can i do it?
As fly is less known company i could not find rom or firmware for higher version for fly tablet.

Is any other rom compatible with the specs?
I need to upgrade it can any body help with info how to do it.