This comes after a whole controversy that it was slowing down performance on older devices with aging batteries. (indianexpress.com)
They bring new firmware updates to their latest e-readers first and then optimize it for older devices too. (goodereader.com)
However, Android 7.0 Nougat was designed to require less hardware resources, so it can play nice even with older devices with specifications that are lower - end by today's standards. (androidheadlines.com)