Listed below are the Esri software products supported by ArcGIS 10.6 License Manager.
Concurrent Use
ArcGIS Desktop 10.6.x, 10.5.x, 10.4.x, 10.3.x, 10.2.x, 10.1 SP1, 10.1, 10.0, 9.x
ArcGIS Engine 10.6.x, 10.5.x, 10.4.x, 10.3.x, 10.2.x, 10.1 SP1, 10.1, 10.0
ArcGIS Pro 2.1.x, 2.0.x, 1.4.x, 1.3.x, 1.2.x
Esri CityEngine 2017.x, 2016.x, 2015.x, 2014.x, 2013.x, 2012.x
ARC/INFO Workstation 10.0, 9.x
Named User (via on-premises Portal for ArcGIS)
ArcGIS Pro 2.1.x, 2.0.x, 1.4.x, 1.3.x, 1.2.x, 1.1.x, 1.0.x
Drone2Map 1.2, 1.1, 1.0