This is a full install and will replace the current Version 5 installer. If you are currently on Version 5 this is a mandatory update as it fixes issues in a variety of areas, including data accuracy, speed, and daily operation. There are also several new items added to the product. Even if you have downloaded and installed the Release Patch 1 for Version 5, you should install this upgrade.
If you are upgrading from Version 4.1 this will upgrade in place, and leave your settings intact. However you will need to reload your data.
Current users of QQube will be sent a link to download the new version. New users need to request the link for a trial download. Installation instructions will be found here.