While everyone is commenting about drm, there is another factor to consider: TLS. These old Kindles definitely do not support up-to-date TLS ciphersuites and understandably Amazon wants/needs to drop insecure ciphersuites from public endpoints at some point. I'm pretty sure that is also the reason why the Wikipedia integration for these old Kindles broke ages ago.
Comments
While everyone is commenting about drm, there is another factor to consider: TLS. These old Kindles definitely do not support up-to-date TLS ciphersuites and understandably Amazon wants/needs to drop insecure ciphersuites from public endpoints at some point. I'm pretty sure that is also the reason why the Wikipedia integration for these old Kindles broke ages ago.
Software updates exist, I’m sure they could support it if they wanted to.
Ed25519 isn’t so new that the hardware wouldn’t be capable.