Postbox 6.1.6

Postbox is powerful, intuitive, ultra-customizable, speedy, and dead set on saving you time. It is derived from Thunderbird.

You can find a list of features here: https://www.postbox-inc.com/features

Please Note: This software is available as a 30-day trial, you must purchase it at the end of the trial period if you want to continue using it.