If you only upgrade Remedy AR System Server and Atrium Core to 9.0, but keeping applications downgraded compatibility patch is required.
This knowledge article may contain information that does not apply to version 21.05 or later which runs in a container environment. Please refer to Article Number 000385088 for more information about troubleshooting BMC products in containers.
If you are only upgrading AR & CMDB to 9.0 and not upgrading Remedy Applications from a 7.6.04 SP2 and above to 9.0 you will need to apply an applications compatibility hotfix bundle. The hot fix bundles should be applied after the upgrade of AR and CMDB have been successfully completed. Hot fixes are available by version and by app – ITSM, SRM, SLM, and PD. Based on version, not all applications will need a hotfix.
This will modify workflow therefore the hotfix bundle is independent of OS platform. The workflow modification will allow deploying the def/arx/drm files into the remedy system.
Application Compatibility Patch links