We are currently using Microsoft Windows Server 2012 R2 with active Software Assurance (SA). Our volume licensing agreement expires at the end of the year. Can we continue to use existing licenses or do we need to migrate to Windows Server 2016?

In this situation, you have the ability to react in two ways:

“Early Commitments for renewal”

After the “General Availability” of Windows Server 2016 (October 12, 2016) and before the expiration of your volume licensing agreement, you have the option to sign an “early commitment” for renewal. This gives you the right to continue to use a CPU-based license even after renewal of the volume licensing agreement.

Conversion of licenses through contract renewal

By the renewal of the volume license agreement, customers who purchased Windows Server with SA will have to convert the old CPU-based licenses to the new core-based licensing model.

In the core-based license model the following conditions apply:

• Licenses are sold in packages to 2-cores
• All physical cores of a server must be fully licensed
• Each processor (CPU) of a server must be licensed with at least 8 cores (four 2-core packages per processor)
• Each physical server (including a single processor) must be licensed with at least 16 cores (eight 2-core packages per server)

For the conversion of the licenses the customer has two alternatives available:

Alternative 1: Automatic conversion

• A Windows Server Standard 2 CPU license is converted into 8 Windows Server Standard 2-core licenses. This license covers a maximum of 2 CPUs per server with up to 8 cores each. Up to two virtual machines may be operated on a fully licensed server
• A Windows Server Datacenter 2 CPU license is converted into 8 Windows Server Datacenter 2-core licenses. This license covers a maximum of 2 CPUs per server with up to 8 cores each. A fully licensed server may run an unlimited number of virtual machines.

Alternative 2: Conversion through infrastructure inventory

• At the expiration of their volume licensing agreement, customers can run an inventory of their environment and deliver the result to Microsoft. The dated result must document all servers, processors, and cores in a productive environment where Windows Server is installed. The exact number of active cores is then credited to the customer and taken into account during the contract renewal. Microsoft recommends the following free solutions for inventory: Microsoft Assessment Planning Toolkit or Microsoft Software Inventory Logging Aggregator. An Inventory Tool from another vendor can also be used.

Sources:

Licensing Datasheet_Microsoft Windows Server 2016

Windows Server 2016 Licensing FAQ as is 2016-09-08

Microsoft Product Terms November 2016