The base file chart section in UNIFI helps to future-proof families when future versions of Revit are used.
To get to the base file chart section, click on the File History tab when viewing details of a family.
In the base file chart section shown below, you can see that this family was built originally in 2016 and UNIFI upgraded it automatically in the cloud for you.
In the photo shown above, here is what each icon represents:
Cloud - the version that UNIFI automatically pulls from the cloud
"No" symbol - UNIFI is no longer pulling that particular version
Square with arrow - The file version of the uploaded file (also referred to as the "base file")
So let’s say that your team is using 2017 for a project, in that case, UNIFI will pull that version from the cloud so that your team doesn’t have to manually upgrade the family. You'll see in the example above that another base file for Revit 2019 was uploaded with changed parameter data. When this happens, UNIFI will then upgrade the 2019 base file for the latest Revit versions.
What UNIFI did here was future-proof this family because now there is a second base file that will be used for future versions of Revit. That means that if any user is using a more recent version of Revit, UNIFI will use the base file of that version, but will still maintain these legacy versions for projects which are using earlier versions of Revit.
In other words, you don’t have to worry about maintaining multiple versions or multiple libraries for versions of programs.