So I thought I had ARC more or less working using Tailscale. This weekend I went to Atlanta [I live near Sacramento] and on both my iPad and iPhone every attempt to use ARC was met with an error message that said " ARC connect connect with this version of Roon Server. Please update your Server."
However, both ARC and my server are on the same version. And now that I’m home, I don’t see any updates.
If your versions are up to date (and you are not trying to run a mix of Early Access and Production versions on server and remotes), then this is a new issue that has recently affected several people. See this thread: