Before you deploy your ArcGIS Maps SDK app into production, you are required to license it. Esri provides four ArcGIS Maps SDK license levels: Lite, Basic, Standard, and Advanced. The license levels required to use some parts of the API are determined by which members of C++ classes you are using, and in some cases what you are using them for. See the following ArcGIS Maps SDK for Qt guide document for details: License by API.