Tableau 2018.1 is just the new release of Tableau. They have changed their version naming convention from 8.x, 9.x, 10.x to 2018.x
Here is a link to the new features
Tableau 2018.1 was released on April 24, 2018. All the features in this version of the software can be found here: What's New in Tableau
You can also explore the features here: Tableau 2018.1 Features | Tableau Software
Just below 2018.1 you can browse summaries of new features for all currently supported versions of our software.
I am going to mark this thread as correct, but please let me know if you have any further questions.