Source code and official binaries for stable releases can be downloaded at download.kde.org.
Windows 7 is minimum supported Windows version.
You can choose between Standard (system-wide) installation and Portable installation which only extracts files and setup the application to run in portable mode by default.
Pre-release installers can be downloaded here.
You should install
falkon package from your distribution’s repositories.
Nightly builds are available in
kdeapps flatpak repository.