What are the steps required to perform an active MUF upgrade from CA Datacom/DB 14.0 or from 15.0? Or from 15.0 to 15.1?
The upgrade procedures were enhanced with CA Datacom//DB Version 15.0 and are now called an "active" MUF upgrade.
The Active Upgrade process is documented in section How to Perform an Active Multi-User Facility Upgrade in CA Datacom Core - 15.0.
Go to the section "Performing an Active MUF Upgrade".
Review the documentation scenario entirely.
The upgrade process from CA Datacom/DB Version 15.0 to 15.1 is even simpler.
Refer to How to Perform a 15.0 to 15.1 Active MUF Upgrade.