How fast start with Qt6 ?

[AndrzejB]

While Qt5 is already installed in my Mint21 Vanessa Qt version 5.15.3
and I installed also from qt-unified-linux-x64-4.4.1-online.run version 5.15.2 (I can't find 5.15.3)
aptitude search qt6 give me 194 results.
Which of them I must install ?
install all qt6version 6.2.4

sudo apt install *qt6*

next, I install more bytes of Qt6 with qt-unified-linux-x64-4.4.1-online.run
version also 6.2.4

Next, I must make cmake files for both Qt5 and Qt6 compatibility.
How to write compatible CMakeLists.txt and choose Qt5 or Qt6 if both installed?
Where is list of differences Qt5<->Qt6 ?

[SGaist]

Hi,

For version less support in cmake see the dedicated chapter in Qt 6's documentation.

As for the differences, there is the porting guide.