I know it is not first message related to this topic and possibly not last. But problem is really hot and important.
Many excellent opensource projects chose OpenCASCADE platform for developing their engineering/scientific software. But even when these programs have licenses compatible with Open CASCADE Technology Public License (OCTPL) they also linked with other commonly used libraries. And in last case we may face with licence incompatibility between OCTPL and GPL.
Such incompatibility leads to hard problem: programs become undistributable in particular or in whole. Sometimes they could be patched to remove their functionality related with third-party libraries, but this is not always possible and this is not a general solution.
For illustration I can give you a list of programs affected by this problem in Debian (it is not a complete list): freecad , netgen , elmer , gmsh , salome . All these programs are valuable, they are widely used in engineering work.
Please have in mind that this is not Debian specific problem. All popular GNU/Linux distributions (like Fedora, Ubuntu, Mandriva and etc.) with strong Licensing Policy cannot distribute programs from the list above as is. (Though for few of them patches could be prepared as a temporary solution).
Also binaries for MS Windows (for example, from installers ) violate licenses of used libraries. But who cares this in the "Windows world"?..
Such problems are demotivating developers and maintainers from volunteering their time into FOSS projects. You have made an excellent opensource platform for development of engineering/scientific software, but it will be useless for FOSS community if we cannot use it in programs bigger than "Hello, world!".
Could you update your Open CASCADE Technology Public License to make it compatible with GPLv2 or later? Remember, that choosing one of already available popular free/opensource licenses is always a good choice (for example, LGPLv2.1 or later). But it is not necessary, the main goal is to solve the problem in one way or another.