KDE Plasma 5.12 LTS is the second long-term support release from the Plasma 5 team. We have been working hard, focusing on speed and stability for this release. Boot time to desktop has been improved by reviewing the code for anything which blocks execution. The team has been triaging and fixing bugs in every aspect of the codebase, tidying up artwork, removing corner cases, and ensuring cross-desktop integration. For the first time, we offer our Wayland integration on long-term support, so you can be sure we will continue to provide bug fixes and improvements to the Wayland experience.
For more details, read on KDE Plasma 5.12 LTS release announcements