SDP - downgrade/upgrade software license

Hi there,

This is what we've been doing:
We have a software license for EndNote X (30 installation allowed), it entitles us for a free upgrade with software assurance.
Then we've decided to upgrade to EndNote X3. So I re-create the license with same info, but different key and software.
And did the same when we upgrade to EndNote X7.

My question is ... some still using the old version for compatibility reasons, so how do I deal with this?
Can I somehow make the previous EndNote version to "see" the license for the latest version?
I see the downgrade option on the license view but don't know how it works.

Thank you for your advice.