Here is an article that references this tool: https://techcommunity.microsoft.com/t5/storage-at-microsoft/microsoft-file-server-migration-toolkit-1-2-available-as-a-free/ba-p/423958
Most recently I’ve been tasked with migrating files between outdate Server 2008 R2 File Servers and newer Server 2016/2019 File Server. While there is an Azure option, there is also a old school option that was discontinued after Server 2008 R2 and its quite useful.
It’s fairly straight forward to use, and perhaps this will help others. 🙂
Download here: File Server Migration Wizard