As Paralog is continually developed and improved it is a good practice to regularly install the latest version.
The current version of Paralog is version 7.2.0, released 2013-02-21. Latest changes can be found here.
Updates within a major version (i.e. moving from 7.0.x to 7.0.y or 7.1.z) provide minor enhancements and bug fixes to Paralog and are free of charge.
Updates across major versions (i.e. moving from 5.x to 7.x) provide major functional enhancements to Paralog and require an upgrade of your license when applied after the 90 day support period. License upgrades can be purchased here.
To install an update, download and run the installer. The update should leave your existing data, settings and licensing information intact. Nevertheless, a backup is never a bad idea!