It might be helpful if you could provide some details, eg. how many agents do have etc.
Personally I could imagine 2 scenarios with pros and cons:
- Apply inplace upgrade from 9.2 to 11.0.x
- Install BES Root and ILMT from scratch and migrate agents
Did I get it right that you use BigFix only for ILMT? In this case, a third option using ILMT without Bigfix might also be a possible way to go.
I would prefer option 2. It would provide a clean, fresh BigFix installation and keep your existing server as a backup running in parallel. You would need a new, additional license.
After installing the new Server (and databases of course) you can migrate the clients using a fixlet which just replaces the masthead file and restarts the agent. In case of need I can provide a code snippet for this.
If you prefer option 1 I would strongly recommend to open a support case to be on the safe side. And as much backups / VM Snapshots as possible.