KWin and Wayland
KDE is pushing to have first class support for Wayland, and Plasma 5.21 makes great headway to reach that goal.
The compositing code in KWin has been extensively refactored and should reduce latency throughout all compositing operations. We have also added a control in the compositing settings so you can choose whether you prefer lower latency or smoother animations.
In addition, we have also added support for mixed-refresh-rate display setups on Wayland, e.g. you can have one screen refreshing at 144Hz and another at 60Hz. Preliminary support for multiple GPUs was also added on Wayland.
The virtual keyboard in Wayland has been improved and now supports GTK applications using the
text-input-v3 protocol. The support for graphical tablets has also been improved and now includes all the controls that were missing in the previous version, such as pad ring and pad buttons.
Apart from the numerous improvements in stability, there are quite a few Plasma components that are getting much better support in Wayland. For example, KRunner is now able to list all open windows in Wayland, and we now support features required for GTK4, so GTK4 application will now work.