Dependencies:
sudo apt install qttools5-dev-tools qt5-default qtbase5-private-dev
git clone https://github.com/qt/qtmqtt.git
cd qtmqtt
git checkout v$(qmake -v | grep "Qt version" | sed "s/^.*version \([5-9]\.[0-9]\+\.[0-9]\+\) .*$/\1/") || echo "Unable to find your Qt version"
qmake && make -j$(nproc)
sudo make install

Update/edit translations:
lupdate -verbose thermostat.pro
linguist lang/thermostat_fr.ts