Hello.
After manual updating from version 2.12.06-raspbian-stretch-stable to 2.18.02-raspbian-buster-stable i have the same issue. During installation there was an error that package libqt5qml5 was not installed, so i installed it via apt (libqt5qml5:armhf (5.7.1-2+rpi1)), and now deconz failed to start.
Logs:
Sep 26 19:08:04 openHABianPi systemd[1]: deconz-init.service: Failed with result 'start-limit-hit'.
Sep 26 19:08:05 openHABianPi deCONZ[12451]: This plugin does not support propagateSizeHints()
Sep 26 19:08:05 openHABianPi deCONZ[12451]: This plugin does not support propagateSizeHints()
Sep 26 19:08:05 openHABianPi deCONZ[12451]: /usr/bin/deCONZ: relocation error: /usr/bin/deCONZ: symbol _ZNK12QFontMetrics17horizontalAdvanceERK7QStringi, version Qt_5 not defined in file libQt5Gui.so.5 with link time reference
Used OS and hardware:
Release = Raspbian GNU/Linux 9 (stretch)
Kernel = Linux 4.19.66-v7+
Platform = Raspberry Pi 3 Model B Plus Rev 1.3