A month or so ago I did a test migration of a few on-prem TFS projects to Visual Studio online. For the most part everything worked. Changesets were migrated over showing th
The OpsHub Migration Utility has been recently revamped. From the v2.0 the tool is been released under two variants.
Some features are not longer a part of the free version of the utility. A complete list of the differences between the two variants can be referred to from the Gallery Page under the Section 2.3.3 Comparison between Free and Commercial Utility
The feature that you are referring to, is impersonation, which is not longer supported in the Free Utility.