Hi Firefox for Android is not available for Kindle, however there is a solution that you may wish to look into if you want to use Firefox on your device. This [https://support.mozilla.org/en-US/kb/installing-firefox-android-amazon-kindle-fire article] will walk you through how to install Firefox on a Kindle device. It is a more technical article, but it should help you install a version of Firefox that will update and have security and stability fixes as well as new features not in the older version you are currently using. If you have any questions, please let me know and I will do my best to help.