Package: qemu-system-x86 Version: 1:2.12+dfsg-2 Severity: serious The various qemu packages that depend on qemu-system-data do so with (>> ${source:Version}), which makes them uninstallable. For instance, qemu-system-x86 1:2.12+dfsg-2 depends on qemu-system-data (>> 1:2.12+dfsg-2).