This tool looks promising when I went through the available information on website. But when I downloaded free version and when I am trying to install in my local I came across the following error.
OPS-008: OpsHub Visual Studio Migration Utility requires Team Foundation Server 2012 Update 1 Object Model or above.
Do I need to install this software on the server ? No where I could find instructions for installing this software. Can I get this explained please, we are planning to migrate our project to VSTS.
If you want to migrate from TFS on premise to VSTS, I would suggest you to evaluate which of the three options listed by Microsoft documentation suite your need.
The easier way would be to chose option 2, especially if you already have TFS2015update3 or TFS 2017, as you need to upgrade your TFS collection to one of those version anyway before migrating (and you save the upgrade hassle).
If you want to use OpsHub tool, then you need to install the standalone TFS Object Model for TFS 2012 update 4 where you run the OpsHub tool, not on any of the TFS servers.