You can now upgrade to the latest versions of KDE’s Plasma, Applications and Frameworks series, built against the brand new Qt 5.10.0.
Applications 17.12.0 are the first release of a new series that focused on introducing enhancements and new features. Several applications are now ported to Frameworks 5, but unfortunately some had to be dropped as they are no longer maintained. Please check the official announcement for the full details.
It should be safe to answer yes to any replacement question by Pacman. If in doubt or if you face another issue in relation to this update, please ask or report it below.
Most of our mirrors take 12-24h to synchronize, after which it should be safe to upgrade. To be sure, please use the mirror status page to check that your mirror synchronized with our main server after this announcement.