Should I use the CIM v.2 or CIM v.3 VSP Engine Tools installer?

VertiGIS Studio Products in general support ArcGIS Enterprise 11.x versions, therefore VSP Engine Tools CIM v.3 installer should be your choice. The VSP Engine Tools CIM v.2 should be only used for non-VertiGIS Studio legacy products only compatible with ArcGIS Enterprise <= 10.9.x. Updates and fixes for VSP Engine Tools are in general forced for CIM v.3 only. Also notice that VGS Desktop Printing also only supports VSP Engine Tools CIM v.3.

Please also see https://support.vertigis.com/hc/en-us/articles/18772434800914-What-do-the-CIM-v-2-and-CIM-v-3-suffixes-mean-for-the-VSP-Engine-Tools-installer