MS Title Group:
Description: A SharePoint Server client access license (CAL) gives a user the right to access the services of SharePoint Server. This device CAL authorizes one computer to access SharePoint Server, regardless of the number of users (for example, a shared workstation).
User CALs are also available. A user CAL authorizes a user to access SharePoint Server from any device (for example, when an employee accesses the server from a computer at work and another at home).
Note: This license does not require media, license keys, or setup codes.
Which Versions of This Software Are Available?
You can choose to download the current or previous version of the software in any language that's available through the Microsoft Volume Licensing Service Center if you request this product. You can find out which version of the software is the current one in the Microsoft Title Groups document.
Software Assurance: Under the Software Assurance program, you have the right to install any new release of products covered in the agreement during the term of your coverage.
Under the Software Assurance program, customers acquire the right to install any new release of products covered in the agreement during the term of their coverage
Product restrictions can be found under Microsoft's eligibility guidelines.