> Technically, what it means is that you need to sell the app and an offer for the source code. Only for the library (and any modifications to it), not the app

> Technically, what it means is that you need to sell the app and an offer for the source code. Only for the library (and any modifications to it), not the app itself. If the developer makes modifications to the actual source code of Qt itself he/she has to release those modifications[0]. He/she does not have to release the rest of the source code of the app. [0] Technically, the Qt source must be provided whether or not any modifications were made, though this is easily fulfilled.