Think it might be something to do with the chips they use in them, IIRC Android versions only support a certain generation of chipsets.
Companies are using relatively older chips in e-reader devices as they have no need for a modern, better one and would likely add unnecessary cost, just to run a more recent version of Android
Most android ereaders are on that version, which is weird when you think about it. I wonder why?
Think it might be something to do with the chips they use in them, IIRC Android versions only support a certain generation of chipsets.
Companies are using relatively older chips in e-reader devices as they have no need for a modern, better one and would likely add unnecessary cost, just to run a more recent version of Android