Default Sensitivity Label to be added to migrated files (from Local Network Server)

Hi Rhey, the reply will probably be way to late for your project. However, we did this task making labels mandatory one year ahead of actually moving to cloud. All labels without encryption, also "strictly confidential" had no encryption. This to observe how well users apply labels according to the content. Training added as required. After applying mandatory labelling, before migration to cloud, we introduced custom protection for label "strictly confidential(enc)". Only migrate "strictly confidential" files with (enc). Users have to manually ammend the custom protection, since this policy is applied per document individually. You can use powershell to buks assign owner and a list ofe one single MIP-custom-role (eg. Restricted Editor) to multiple files to assist your clients. The new MIP Client can do bulkupdates as well. Then we used s h a r e g a t e to migrate required local SharePoint / MS Teams to cloud and made the on-prem stuff read-only for max 2 years.