Hi John! Sounds more like a hardware issue with the phone. I have the same phone as you and after dusting it off from the drawer and installing Jelly it was working OK (no flicker, only some lag because of an ancient Android version) You could try a factory reset of the phone to see if it solved the issue. Don't forget to…
King will likely completely abandon their website and go mobile/tablet exclusive. The fact that they haven't added Candy Crush Jelly Saga to their site yet is proof of this.