Autodesk released news recently of an important news for companies using older versions of Autodesk products. Derek Gauer posted on Linkedin here – https://www.linkedin.com/pulse/autodesk-news-previous-release-usage-derek-gauer/
Autodesk is tightening up the way that they enforce technical support for previous versions of Autodesk products.
If your company is using Autodesk product (2016 or earlier), after August 31, 2019 you will not be able to re-authorize the software. This can happen if you are changing computers or moving a standalone license between computers. This will also be an issue in getting a new license file for a previous release for a network license server.
Organizations will have to update to a minimum of a 2017 product or greater. Drawings should be included in the process, to make this a smooth transition.
For more information, please look at this article on the Autodesk Knowledgebase: