Downgrade/Upgrade: These are specific software entitlement rights. Downgrade rights permit a user to run a previous version of the software, while upgrade rights (often included in maintenance or subscription) entitle a user to future versions as they are released.

Software Subscription: This is a licensing model where the right to use the software is granted for a finite, recurring period (e.g., monthly or yearly). Use is contingent on payment, fitting the definition of "a limited amount of time."

Client Access: A Client Access License (CAL) is a common license type in server environments. It grants a specific user (User CAL) or device (Device CAL) the legal right to access and utilize the services of a server product.

Publisher Pack: In Software Asset Management (SAM) tools, a Publisher Pack is a data add-on that provides publisher-specific licensing rules, product use rights, and reporting templates. These are used to populate and run compliance dashboards.

Downgrade/Upgrade (Downgrade Rights):

Source: Microsoft Product Terms

Reference: In the "Universal License Terms" section, under "Software," the "Downgrade Rights" subsection details the specific entitlements for using prior versions of software for which a customer is licensed.

Software Subscription:

Source: Microsoft Licensing Documentation

Reference: The "Subscription licensing" overview explains that subscriptions provide "rights to use software products... for a defined period." This contrasts with perpetual licenses, which grant rights "in perpetuity."

Client Access:

Source: Microsoft Licensing Documentation

Reference: The "Client Access Licenses (CAL) & Management Licenses" guide defines a CAL as a license "that gives a user or device the right to access the services of a server."

Publisher Pack:

Source: Flexera (Official Vendor Documentation for SAM tools)

Reference: The "FlexNet Manager Platform" documentation describes the "Application Recognition Library and Publisher Packs" as containing the necessary data (SKUs, use rights, rules) "to build reports and dashboards" for managing software compliance and optimization.