downgrade

Using an earlier release (or version) of an application under a license covering a later version; or using a lesser edition under a license for a more powerful edition. These rights are usually granted in a license agreement subject to other conditions, such as their being continuous maintenance in place. Software publishers may interpret a downgrade right in at least two ways, for which you should carefully check the license agreement and any over-arching purchase or support agreement:
  • Backward-compatibility model. To protect from possible backward compatibility problems, some publishers permit the licensed release and an earlier release to be installed simultaneously on the same computer for use by the same user. The two installations of the product will consume only one entitlement. For example, see the licensing of earlier versions of Adobe Photoshop. In this model, the use of different releases on separate computers by different users is often specifically or implicitly excluded — each such separate use will require a separate license entitlement. This model commonly occurs when you purchase a separate upgrade license.

  • License aggregation model. Usually only under purchasing agreements, some publishers allow the one, current license to cover installations of the current release on some of the computer fleet, and installations of earlier releases on separate computers. For example, examine the terms of the Microsoft Select License and Select Plus agreements. Usually in this model, each computer may have only one installation of the product (regardless of which release). If the agreement specifically excludes multiple installations, you may also need to adjust the Right of multiple use setting on the Use rights & rules tab.

Check your agreements carefully. Do not assume one publisher uses the same agreement across products, or over time. For example, an early license for Adobe Creative Suite allowed a downgrade right to earlier versions of Photoshop, but not to Acrobat.