I’m playing around with XML transformations today and needed a refresher. This is a pretty good explanation straight from the horse’s mouth.
https://msdn.microsoft.com/en-us/library/dd465326(v=vs.110).aspx
I’m deploying to an Azure website, in which case there are ways to keep connection strings and app settings unique to each slot of your website. https://azure.microsoft.com/en-us/blog/windows-azure-web-sites-how-application-strings-and-connection-strings-work/
However, the setting I need to tweak for production isn’t an “app setting”, but rather a servicemodel client endpoint, which apparently has to be done the hard way. 🙁