I see on the X.org announcements list xorg-announce@lists.x.org that "X server [21.1.0] now correctly reports display DPI in more cases. This may affect rendering of client applications that have their own workarounds for hi-DPI screens."

Leslie -- Operating System: Linux Distribution: openSUSE Leap 15.3 x86_64 Desktop Environment: Trinity Qt: 3.5.0 TDE: R14.0.10 tde-config: 1.0