a true Sandbox that stays in synch with Production?

@TwoDog 

DocuSign eSignature Sandbox and Production are hosted on different server environments that are not connected to one another. Therefore, if you request changes you need to request them for both environments to keep in sync and if you manually change settings, you need to do it in both environments.

In terms of new features they will be made available to the Sandbox environment, typically 2 weeks before they are then pushed into production. Therefore, there will always be a period of time both environments are not in sync in regards to the latest features and fixes being available in production.

How does a “Demo” account factor into this equation? 
Would a Demo account mimic a Production account ? 

The confusing point here is the term “Sandbox”  
I am 30 years IT and this term is usually a “push to Production” process.