If you encounter issues, Bentley recommends uninstalling previous versions and ensuring Microsoft .NET Framework 4.8 is installed before re-running the installer. ISM Revit Plug-in - Bentley Systems
(Intelligent Script Manager) software, developed by C-DAC GIST
Disclaimer: The exact URL for Version 63 changes frequently as archives are updated or removed. Below are the standard methods to retrieve the valid link.
Based on technical specifications and user feedback from sources like C-DAC and Indian Express :