The release notes for flowmon-1.4.0 package contains a summary of the changes made since flowmon-1.3.0 package. It describes recently added, changed or deleted tools or other features of FlowMon project.
flowmon-1.4.0 package is available at http://www.liberouter.org/clients/. Process of installing this package is described in README file inside the package. Information about FlowMon project can be found at http://www.flowmon.org.
FlowMon 1.4.0 is a release distribution. This package contains installation framework with liberouterpkg tool to enable easy package switching and uninstalling. Due to this you have to fully uninstall any previously installed Liberouter package that doesn't contain liberouterpkg tool (liberouterpkg tool is part of the FlowMon package since flowmon-1.3.0).
If you are upgrading from a flowmon-1.3.0 package you can install this package release directly. After installation flowmon-1.4.0 package will be installed as active Liberouter package. To switching or uninstalling package(s) please use liberouterpkg tool.
In the other case (you have never installed Liberouter package with liberouterpkg tool) please remove ALL previously installed Liberouter tool (including libraries and drivers) first.