According to this change in Qt 5.12 https://codereview.qt-project.org/#/c/222788/ there is a possible binary compatibility break in Qt 5.12 on Mac OS.
Example: A company has created, released and delivered Qt libraries to their customers. These libraries are built with for example Qt 5.10. A customer updates their Qt version to 5.12 and creates a new application using those libraries that above mentioned company has released. When a customer runs the application in debug mode, there is a crash because both release and debug versions of Qt libraries are loaded. Release versions comes form libraries that a company has released, and debug versions comes from the new application that was launched in debug mode
In order to prevent the crash, a company has to deliver debug versions of the libraries as well, and customer needs to add a logic in the new application's .pro file to use either release or debug version of the libraries. Is there alternate solution to this problem?