: The recommended version for users on ArcGIS 10.8 is HEC-GeoRAS 10.8.0.3 .
Technically, official support from the USACE Hydrologic Engineering Center (HEC) for GeoRAS ended after version 10.2. However, later versions have been made available via the Esri FTP site to support subsequent ArcGIS Desktop releases: hec georas for arcgis 10.8
To run HEC-GeoRAS on ArcGIS 10.8, your system must meet specific software prerequisites: : Must be version 10.8.x. : The recommended version for users on ArcGIS 10
: Users on older builds may still see version 10.2 as the "official" verified version, but it may require workarounds on newer Windows operating systems. System and Software Requirements : Users on older builds may still see version 10
Using HEC-GeoRAS for ArcGIS 10.8: Compatibility and Best Practices
: Version 4.2 or later is required for full functionality, though HEC-RAS 5.0+ is highly recommended for modern modeling. Core Functionality
: Users digitize river centerlines, banks, and cross-section cut lines from a Digital Terrain Model (DTM) or TIN.