Using Older Versions of Microsoft Software
When a new version of software is released, the older licenses are discontinued and are no longer available for purchase. The older media is available, but a current Microsoft license must be purchased to go with it. You must purchase the current license and “downgrade” it for use with an older version.
How to "Downgrade" Your License
A product that customers often "downgrade" is Microsoft Office. In 2016, Microsoft Office 2013 was replaced by the updated Microsoft Office 2016. Office 2013 licenses were discontinued and no longer available.
1. Order the older product as a media disc. If you wanted to purchase Office 2013, the product can still be ordered as a media disc.
2. Purchase a current version of the license. You would need to purchase an Office 2016 license, the current version, to accompany your Office 2013 media disc.
3. Install the older version of the software to "downgrade" your license. Using your Office 2013 media disc, you would install Microsoft Office 2013 and therefore "downgrade" your Office 2016 license in the process in order to use the older software.