There are two methods and both should ensure your current settings, accounts and stored mails remain intact. The methods are...
1. If you have purchased a license key, you can simply select the 'Update' button on the 'Help' dialog.
2. If you have not yet purchased Ability Mail Server, then you will need to re-download and then reinstall the application. Before you perform the reinstallation, you will need to close Ability Mail Server.
Please note that updating or reinstallation will overwrite important installation files. This also includes the default WebMail and Remote Admin files. We strongly recommend making a backup of the Ability Mail Server 2 folder before updating.