ArcGIS 10.3.1 is available as a free, public download. Legitimate acquisition requires a valid license from Esri or an authorized distributor.
Users within a site license (e.g., Educational Site License) should obtain the installer from their internal software portal or IT department. Downloading from unverified third-party websites is strongly discouraged due to security risks and license violation. i--- Arcgis 10.3.1 Download
Procedural Guide for the Acquisition and Installation of ArcGIS 10.3.1 ArcGIS 10
