Currently (January 2021), the XV4 64-bit version of Q++Studio supports QuarkXPress versions, from QuarkXPress 8 to QuarkXPress 2020, inclusively.
However, not all versions of QuarkXPress are supported by all versions of Windows, and vice-versa.
Quark-Windows Restrictions and Incompatibilities
•QuarkXPress 8 can only run on Windows 7 (not on Windows 10).
•QuarkXPress 2019-2020 can only run on Windows 10.
Topic 182260, last updated on 15-Jul-2020