What are the requirements for a step-up from a lower to a higher level edition?
You are entitled to a step up if the following prerequisites are fulfilled:
- A lower level edition license must be available
- Active Software Assurance (SA) must be available
- You have to be enrolled in one of the following volume licensing programs: Open License Value, Select License, Select Plus, Enterprise Agreement, School Enrollment, or Enrollment for Education Solutions (CASA+EES or OVS-ES).
Source: Volume Licensing Brief_Microsoft_Step up Nov 2013