"Of course it runs FreeBSD, too" is something I said a lot in the past week (regarding the Pine64, mostly, but also about my Slimbook). I also said "Of course it runs on FreeBSD, too" a lot. Naturally area51, the unofficial KDE-FreeBSD ports tree, contains the latest in released KDE software. Plasma 5.12 and KDE Frameworks 5.42, with Qt 5.9.4. We just bumped Qt to pick up a patch from KDE's Eike Hein to fix some weird hover behavior. So we're all up-to-date on the KDE front, and I've been running it as my main desktop since the build finished in poudriere.
On the official ports front, Qt 5.9.4 and KDE Frameworks 5.42 are what we've got. There's a big move coming up of KDE4 ports, which is to make room (in a sense) for KDE Applications and the Plasma Desktop ports. If you're using KDE4 from ports, then expect package bumps and renames over the weekend (no functional change, just a lot of ports will get a -kde4 name to distinguish them from the currently-maintained, up-to-date un-suffixed ports which will land afterwards.