Hotline Connect (referred to as 'Hotline') and Haxial KDX (referred to as 'KDX') are client/server software, reminiscent of older BBSes. The differences from classic BBS systems lies in their Graphical User Interface (GUI) foundation, both clients and servers initially released for the Mac platform with Windows shortly after.
For Windows, the recommended client is:
Hotline Connect Client 1.9.1 - Super Tracker Edition
hlc1.9.1-SuperTrackerEdition.zip
This works well on Windows up to 10 (but feel free to try Windows 11, it might work), and allows access to all the most recent features as of 2003.
Hotline Connect Client 1.9.1 - Super Tracker Edition (Windows)