For 2018.2 you should be aware that the Read Only site role (that was rolled out in 2018.1) is now deprecated. So any users assigned to that role will now be reassigned to the Viewer site role in 2018.2
You could ask the server or site administrator to go into the Users area and review some of the Site Roles you have for folks to make sure you're happy with them, but apart from the Viewer change I don't think you'll see anything else different in 2018.2.
"When you add users to a site on Tableau Server or Tableau Online, independent of their license type, you must apply a site role to them. The site role signifies the maximum level of access a user can have on the site." Set Users’ Site Roles
Hope this helps
[Program Manager - Tableau Community]