I always recommend customers migrating to Splunk Cloud first upgrade their on-prem instances to a version close to what will run in Cloud.  This help ensure a successful migration and also helps ensure instances that will remain on-prem (heavy forwarders, for example) will be compatible with Cloud instances. A 6.5 system likely has many apps are that are too old to be compatible with Splunk Cloud.  Upgrading before migration gives you the chance to test new app versions in a known environment.  The same goes for dashboards that may not be ready for Cloud. Finally, migrating your data to Splunk Cloud requires the use of SmartStore, which requires Splunk 7.2 or newer. ... View more