As of July 2018, the latest available and supported version is KDE Applications 18.04.2, Frameworks 5.47.
You can tap this repository into your Homebrew. It adds KDE Frameworks 5 packages (and all their dependencies) and some applications that already make use of them (e.g. Kate and Kwrite). As of January 7th, 2018 the repository still is experimental as the developer tries to get them into a working state. Hints and patches are welcome.
Please carefully follow installation instructions.
As of October 2017, the latest available and supported version is KDE Applications 4.14.3.
Instructions are provided on TechBase for installing a development environment using MacPorts. If you want a user installation then just skip the final 'Configure your KDE development environment' section.
As of October 2017, the latest available and supported version is KDE SC 4.14.6.
The Fink packages allow you to install KDE SC 4 as either Qt/X11 or Qt/Mac (native) packages by selecting either packages ending in "-x11" or "-mac", for example "kdebase4-x11" and "kdebase4-mac".
Additionally, the Fink packages allow the running of the Plasma desktop in X11 mode. Just install "kdebase4-workspace-x11" to install it.
The Fink KDE software packages will be installed in /sw/opt/kde4/x11 or /sw/opt/kde4/mac respectively. They also are able to start D-Bus for you as long as you run "/sw/bin/init.sh" normally, or when you open a terminal, if you have run the path setup script in the Fink installer.
Please see the distribution notes for MacPorts / Fink / Homebrew formulas you are using. You may need to run the following steps once after installation:
sudo chown -R $USER ~/Library/Preferences/KDE sudo launchctl load -w /Library/LaunchDaemons/org.freedesktop.dbus-system.plist
Sometimes, Installer.app fails to run the post-install. If things are acting funny, try running these two commands in a terminal:
sudo launchctl load -w /Library/LaunchAgents/org.freedesktop.dbus-session.plist /opt/local/bin/kbuildsycoca4