Getting a hold of an offline installer for Qt 5.15.2 can be tricky because, starting with the 5.15 release, the Qt Company changed its distribution model. Official offline installers for version 5.15 and later are generally restricted to commercial license holders
If you have a commercial license, you can download the offline installer directly from the Qt Account Portal : Sign in and navigate to the download qt 5.15.2 offline installer
Tips and Variations:
qt-opensource-windows-x86-5.15.2.exe (Note: Filenames may vary slightly based on architecture).Source Code (Manual Build):If you must have an offline setup, you can download the source code and build it yourself. The source packages (tar.xz or .zip) are available in the official archive. Third-Party & Alternative Methods Install Qt creator 5.15.2 - Qt Forum Getting a hold of an offline installer for Qt 5
For open-source users, the standard route is to use the Qt Online Installer, which still allows for the selection of older versions like 5.15.2 during the installation process. Strategies for Accessing Qt 5.15.2 Example filename: qt-opensource-windows-x86-5