Hi Vishesh,
Ops Manager supports upgrade and downgrade operations for standalone, replica sets, and sharded cluster. See OpsManager: Change MongoDB Version more info.
Note that OpsManager Application is part of the MongoDB Enterprise edition, which is a commercially supported product. If your company already has a commercial subscription and you have further questions about running OpsManager, for faster response I would suggest to open a case in the Commercial Support Project in MongoDB Jira.
Alternatively if you are evaluating MongoDB Enterprise and interested, I can request a MongoDB Account Executive to get in touch with you.
Kind regards,
Wan.