Can you tell me, what are the limitations of developer version of ArcGIS Runtime (especially for Qt)?
Are all features enabled there?
Are you referring to the "Developer" license level? If so, everything is enabled when it is "Developer" mode. This is discussed in our Guide: License your app—ArcGIS Runtime SDK for Qt | ArcGIS for Developers
Here is an excerpt from the above link:
You can download and install an ArcGIS Runtime SDK using an ArcGIS for Developer account. You then have access to all of the functionality in the API for development and testing purposes. In this mode the app will adopt the following behavior:
Retrieving data ...