The Esri Roads and Highways10.3.1 for Server setup package is designed to detect and upgrade an existing installation of Esri Roads and Highways 10.3, 10.2.x, 10.2, or 10.1 (including SP's) for Server to 10.3.1.
All Esri products earlier than release 10.1 need to be uninstalled before installing Esri Roads and Highways10.3.1 for Server.
Esri strongly recommends that all sample and third-party extensions or plug-ins be uninstalled before installing a newer release of an Esri product.
Roads and Highways for Server 10 and earlier users
You must uninstall releases 10 and earlier of Esri Roads and Highways for Server from your machine.