Adds optional PyQt6 support with the "--use-qt6" flag. PyQt6 is automatically used if PyQt5 is not found.
Breaking backwards compatibility with PyQt4 and python2 was necessary to be able to use PyQt6.
PyQt6 requires PyMuPDF to be installed, as there are no Python bindings for poppler-qt6.
My suggestion would be to move to PyQt6 + PyMuPDF (with PyQt5 and perhaps python-poppler-qt5 as a fallback) as the default in the future.
Adds optional PyQt6 support with the "--use-qt6" flag. PyQt6 is automatically used if PyQt5 is not found. Breaking backwards compatibility with PyQt4 and python2 was necessary to be able to use PyQt6. PyQt6 requires PyMuPDF to be installed, as there are no Python bindings for poppler-qt6.
My suggestion would be to move to PyQt6 + PyMuPDF (with PyQt5 and perhaps python-poppler-qt5 as a fallback) as the default in the future.