HI Richard,
In addition to the above response, I have identified that the version are defined in a properties files at the location mentioned below -
<USS_HOME>Self Service\OSOP\portal-ext.properties
Search for below 'openspace_version' parameter and a version number is defined accordingly.
For Service Management 14.1, openspace_version=4
For Service Management 17.0, openspace_version=17
Hope the explanation is helpful to plan your upgrade.