1. Processor Operating Systems are upward compatible: updating a processor with a higher Operating System version is always allowed

2. It is recommended to always upgrade the OS version of a processor with the latest available version

3. It is recommended that the Copro version is associated with the OS version indicated in the QUANTUM - Launch History tables (mandatory for HotStandby Systems)

4. It is mandatory to upgrade the Ethernet Coprocessor before the Processor OS

5. It is not recommended to downgrade the OS of a Processor