Prior to the migration, note these and take appropriate action:

1. Ensure that you schedule or apply all the release updates prior to the migration to avoid not being able to rollback.
   The option to revert to the Branch framework gets disabled after 60 days from the migration date or an Application update, if it happens first post migration to the Sandbox framework.
2. As a pre-clean up task, create a Semantic Model Extensions bundle of the published branch prior to making any semantic model extension changes.
3. Delete or enable disabled steps in the Main branch to be migrated because the migration process migrates only the enabled steps.
4. Delete or merge all unpublished branches because these won’t be migrated.
5. Merge the published branch with the main branch.
6. Publish the Main Branch, confirm that all steps are error free, and confirm that all the subject areas and security referenced in workbooks operate as expected.
7. As a post-clean up task, create a Semantic Model Extensions bundle of the published Main Branch.
8. If you've multiple instances such as development, stage, and production, prepare a semantic model extension migration timeline for each instance. After the initial instance is migrated, it won't be possible to bundle the semantic model extensions until the target instance is on the same semantic model extension framework. It's recommended to complete the migration of the production instance, promptly after migrating the lower instances to avoid bundle delays.