PostboxExpress 1.0.1 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The most popular version of PostboxExpress for Mac is 1.0.
This software for Mac OS X was originally developed by Postbox, Inc. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. PostboxExpress for Mac lies within Communication Tools, more precisely E-mail. The bundle identifier for this app is com.postbox-inc.postboxexpress.
From the developer:
Postbox is a fully featured email solution that provides powerful search, organization, and productivity tools for busy professionals. It contains a much larger feature set, more frequent releases and a faster pace of innovation, which makes Postbox feel more "alive" and relevant than other desktop email clients.
You may want to check out more software for Mac, such as Hogwasher, MailStewardLite or Encrypt Email, which might be similar to PostboxExpress.