The Send to Kindle app for PC and Mac has been updated to version 1.1.0.254. (The previous version was 1.1.0.253.)
It now accepts EPUBs and still allows MOBI format. You can download the latest version kindle app for Windows and Mac from Amazon's website. If you already install the earlier version Kindle app on your computer, you can update to the latest Kindle app by launching the Kindle app and clicking Download and Install.
Amazon added support for sending epub files to Kindle back in April, and their Kindle apps for iOS/Android have supported epub files since August. Now their desktop kindle apps for Windows/Mac also allow users to send epub files to Kindle eReader and Kindle reading apps. Of course, they only support DRM-free epub files. At the same time, they don't actually send the EPUB files to Kindles, but they get converted to Kindle formats instead.
By the way, sending epubs to Kindle by web is better than sending via these Kindle apps. First, it doesn't require you to download the Kindle apps. Second, the send to Kindle by web provides feedback on the processing of the book after it has been sent to Amazon.
