Detecting version used
Navigate to login page of your WebMail Pro installation and once the page is opened, view its source code (e.g. Ctrl-U in Mozilla Firefox). At the bottom of the code, you should see something like:
<!-- 9.6.1.build30-build-a3 -->
This means that WebMail Pro version 9.6.1 (build 30) is installed.
Alternately, if you have filesystem-level access to the installation, check VERSION file in root directory of WebMail Pro installation, it contains the version number.
Another way to check that in WebMail Pro is to log into /adminpanel/
as superadmin and open 'About' tab of admin interface, you should see something like:
About
Name: Afterlogic WebMail Pro PHP
Version: 9.6.1.build30-build-a3