So your CRM Online test environment is scheduled to be upgraded to the Fall 2014 (CRM 2015) release next week. To get ready for it, you log in to the Office 365 console and refresh the organization to ensure that a current copy of your production environment gets upgraded to get a realistic test of your production upgrade. Great! Smart move.
One thing to look out for is that if you have already confirmed your upgrade date for this environment, refreshing the organization will cause your upgrade date to get changed to the next default date (which may be 3 months from now).
After the organization refresh is complete, check the scheduled upgrade date. if it is moved, you can move it back.
Just went through this today with backend support team and there is a valuable piece of information to add: after copying your Prod instance to a Sandbox instance, the upgrade date will be cleared until a system job is run (currently scheduled for Mondays and Thursdays).
Until the system job is ran, the Org shows as “Congratulations! You have the latest update of Microsoft Dynamics CRM” (even if the org is still Spring ’14 Update).
If you copy your Prod instance on a Friday (as I did) you’ll need to wait until Tuesday to have the ability to reschedule the Upgrade.
Hope this helps,