Okay, the issue here is with your cable box.
It is not a tv problem, your tv is an old (2009) model, and not a smart tv. It has no way to detect if there is a new firmware available, and cannot generate that message on its own. There are also no current updates for your tv that would apply here.
Try rebooting your cable box by unplugging power to it for 60+ seconds, which will usually force it to update.
If no change, you'll need to call charger, and they will send an update signal to the box, which may take another day or 2 to take effect,
and if still no change after that, they'd need to replace the box for you.
I believe the issue of switching to bluray is coming up because of a glitch in the cable box firmware which results in lost signal and that prompts the tv to switch over to the enxt input.
You can mitigate that by going into the tv settings menu and disabling the viera net (hdmi power/cec/control) functions.