Access to your library continues to be available with free apps on phone, or Windows, or a newer Kindle as well as any browser, so the loss of support of 14 year old mobile devices doesn’t seem like huge news. There can’t be too many still in use even.
I replaced the battery on my kindle 4 not that long ago. It had the best UX for extended reading when compared to newer kindles.
The biggest downside was not having a frontlit display.
I recently switch to an xteink x4, and found that several others in that community migrated from kindle 4s as well. So there are still some number of users in the world that value the device.
