Based on Qt 5.12 and KDE Frameworks 5.66
KDE Project has announced the next KDE Plasma desktop environment LTS series will be a KDE Plasma 5.18, and plans to release (the exact date is tentatively scheduled for May 2020, February 11) at the beginning of next year. In the release there will be a KDE Plasma 5.17 the previous version 5.18, will be released on October 15.
LTS series of current KDE Plasma is KDE Plasma 5.12, which recently released a series of updates which period last maintenance update - KDE Plasma 5.12.9 , which means that it has reached EOL phase, will no longer provide updated unless the need to address serious security problems or errors.
KDE Plasma major update 5.12.9 LTS include Trashcan applet plug-in support, using the same desktop icon shadow settings, folder view to improve the clarity of the label, improved runner dictionary to find the definition, restore and support from the current desktop session .
Therefore, KDE team with major Linux distribution developers had a conversation to discuss the LTS series which KDE Plasma desktop environment most suitable for them, the largest of two releases chose KDE Plasma 5.18.
KDE Plasma 5.18 LTS based on Qt 5.12 LTS and KDE Frameworks 5.66, also compatible with Qt 5.13, to support use on more releases. Finally, the project also revealed KDE Plasma at 5.18 LTS LTS series will be a KDE Plasma 6.0, but the release date has not been announced.