When you try and install InfraWorks 360 2017 and have a previous version loaded, you will see the following message:
In other versions, you could make the update without removing the previous version. For example: updating from 2016.3 to 2016.4. You could do this because the versions were within the same release year. To move to a new release year: 2016.4 to 2017.1, it is necessary to manually remove the previous version.
Willy Campbell