I just checked it now: The link from the 5.4 announcement in this forum to the download page and all download links on that page seem to work for me.
But maybe it was because the link was still using "http" instead of "https" and some browsers may not like "http" anymore. So I changed it to "https". Verified it still works for me (I use Firefox, but it shows now "https" in the link urls).
So please give it a try.
Your WebRailRoader
Detlef Pump