A useful reference article on New Version Rights on the Microsoft Volume Licensing Blog – especially perhaps if SAM is your thing. Key takeaways:

• Use the Product List’s “Date Available” column to confirm the date needed for active SA for rights to run a particular version of the software
• Confirmation that the latest version does not have to be deployed when SA expires for customers to retain rights to deploy it later – with perpetual licences of course.

Find the full article here: http://bit.ly/1ksOR2e