You still haven't provided an "objective". Assuming you get some form of SQL Server Compact Edition on the Windows Phone, what then ? What's the goal? What do you want to have happen? You talk about a small amount of data to "synchronize", but provide no detail on just how much data we're talking about, or the nature of the data, nor do you provide any reasoning on why there's a need to synchronize it with a SQL 2014 instance. And then you want best practices? Best practices for what, exactly? As so many of the "online games" that are in the "APP" space on cell phones in general quite likely synchronize their data with various differing platforms, there may not be much beyond the inherent security of the connectivity to which to apply any best practices. And, I might add, a "Windows" phone is no more (or less) secure than a Windows PC or tablet. You need to define a detailed and specific objective before you can worry about best practices.