These documents aren't referring to changes in the product versions (i.e. this is not an out of the box difference between versions) but rather they are changes to the individual implementations of Clarity belonging to CA that partners and contractors may be using as part of their collaboration and involvement with CA Services on projects.
These include some 'add-on' types of customizations (such as real time validation of timesheets) that may or may not be available for purchase for use with other Clarity systems and versions that have been developed (and supported) by CA's Services and Global Delivery teams, including for use and deployment in On Premise installations usually.
I hope that helps clarify.