I have a question about the long term sustainability of applications made with WAB developer edition. My organization is considering making WAB dev apps for our needs and then deploying them to our personal servers. We wanted to know how future proof an approach like this would be. With a WAB dev app, I noticed that the only external dependencies are the Web Map, and the ArcGIS JS 3.x API. The rest of the resources the app needs to run are self contained in the app's code. So, I was wondering, is there a danger of ESRI getting rid of the 3.x API anytime soon? If not soon, in 20 years is that a concern? Am I correct that this is a concern for the future sustainability of WAB apps hosted on our servers?