Another major point release in QT is starting to happen in Sid.
https://release.debian.org/transitions/html/qtbase-abi-5-6-1.html
This will impact LXQT as well as the KDE Plasma 5.6 etc.
So, five days from now, pay a little extra attention when apt full-upgrade or apt-get dist-upgrade, aptitude ... for anything dealing with QT5
As always "apt-get" with the "-s" flag is your friend and shows a simulation of what will occur.