Yes, it's an old thread, but I think I may have an answer. I recently downloaded and installed Smart Audiobook Player from Google Play Store on my Kobo Vox. Many Android apps will now say they're not compatible with your device when you try to download them, but this one worked and actually downloaded and installed an older version (2.2.0b) that's compatible with the Vox's old Android version. The OP's best bet is to search on line for anolder Kindle version that's compatible. My Vox recently crashed and I lost a lot of my apps, including Dropbox. Unfortunately Dropbox no longer has an older version that's compatible and it's nowhere to be found on the net.
