Hello again,
Question: Where the layer files regenerated, or newly created, for SQL Server or was the data source just updated?
.lyr files were created in ArcGIS 10.2 with SDE Oracle. All .lyr files were copied in a new folder, and datasource updated with ArcGIS 10.4. to point to SDESQL.
Are both systems (Oracle and SQL Server) live during the migration, or have you already shutdown Oracle?
We are currently migrating in a development environment. Both systems are live by the moment.