This page feels a little bit unloved - would it perhaps make a bit more sense to be posting these on the "data model status" thread?
I had been told to check the "status" thread for this latest version of these tools (by a representative of Safe, who thought that's where it would appear), and hence have only just discovered it today, 2 months after you posted it!
Is the zip file included here the latest version of migration tools? If it is on the Data Model thread, can you please post the URL to that thread?
Also, there is another reference to loading Water data into UN specified at Overview—Get Started | ArcGIS Solutions for Water Is this the same toolset? If not, what are the differences and which is better?
Vish Apte the last published version is attached to this thread. Going forward we are no longer updating the migration tools with each update to the Water Distribution Utility Network Foundation. Savvy Data Interoperability extension users or FME users should be able to easily modify the zip file to reflect the input of the most current asset package.
Another option to load data into an asset package for loading into a utility network is the Data Loading Tools. This is a configuration of the Data Loading Tools for loading a typical water distribution geometric network to a utility network - Water Distribution Utility Network Data Loading | ArcGIS Solutions for Water This is not the same toolset as the Migration Tools and does not utilize the Data Interoperability Extension or FME.
In my opinion, neither the Data Loading Tools nor Migration Tools are "better". Rather they are different tools you can use to get the job done. The Migration Tools are really just showing you how to leverage FME or the Data Interoperability Extension to load data to the asset package. For skilled FME / Data Interop users or data translations that require a substantial geometry manipulation, you may be better using the Migration Tools approach.
The Data Loading Tools may be a better fit for users that don't have experience with FME / Data Interop and their source data doesn't require a lot of geometry manipulation. It also may be a better fit for users with a target schema that is close to the typical industry representation of a water distribution system (i.e. a geometric network with the Local Government Info Model or Water Editing Tools schema).
Hope that helps.