Starting from IMS 10.1, SMU is no longer supported. SMU has to be converted to CA Top Secret rules.
Do you have to convert to CA Top Secret rules, before upgrading to IMS 10.1 or above.
Or can you convert after upgrading to IMS 10.1 or above. If yes, how?
Converting to CA Top Secret from SMU can be done before or after upgrading to IMS 10.1 or above.
For more about the CA Top Secret SMU conversion, please see the CA Top Secret for z/OS Implementation Guide; chapter 5 Implementation Security for IMS for CA Top Secret r15.0
For CA Top Secret r16.0, go to docops.ca.com site; signon; choose your product CA Top Secret for z/OS - 16.0; click on "Implementing in CICS and Other Interfaces"; click on "Implementing Security IMS" for more details about SMU conversion.