Is lagging behind the latest version

In itself, a very good app. Use supplies already from the Google Play Goals. To synchronize on Kindle my deliveries, I allowed myself the Pro version.
Unfortunately Amazon's version is outdated and the Future of synchronization via deliveries account only works with a later version of the program. Under version 4.5, the Future has been disabled. In Amazon Appstore I can only load the Version 4.4.1. And my Google Account, it can not be on the Amazon Kindle to yes. Also, the addition of the Amazon account is not possible.
So paying double for nothing and 1.45 invested for nothing.

The program itself would have its 5 star rating! The Google version I use for a long time without problems on smartphone and Android tablet.

Update 04/14/2014
Even though I have "automatic update" feature enabled on the Kindle, this app has not been updated. I was denied the offered in the AppStore version 4.5.1. Only a manual uninstall and reinstall then brought the desired success.
Synchronization via 'deliveries account' works well, adding the Amazon account's is still acknowledged with an error message.