Check Versions
Is this is a Major version update or a Minor version update? You can check the version of your Ignition in several ways. The easiest way is to log into the Status section of the Gateway Webpage, and select Systems > Overview. The version is listed on the Overview page under Architecture.

It is a MINOR VERSION upgrade if only the last number changes. IE: from 7.9.1 to 7.9.3.
Minor version changes are mostly bug fixes. These are minor changes to Ignition and will fall under your existing license.
You do not have to update your license.
It is a MAJOR VERSION upgrade if one of the first two version numbers changes. IE: from 7.8 to 7.9, or from 7.9 to 8.0.
Major version changes are very large changes to Ignition. These will add functionality or change the way some of the systems in Ignition work.
You do have to update your license.