If you want to help test a workaround (disables TLS 1.3) for this issue see:
https://github.com/torproject/tor/pull/625
Nick wrote (https://trac.torproject.org/projects/tor/ticket/28973#comment:2 ):
> I expect that a few warnings will still happen with this branch: it waits
> for the bug to happ
Thank you all for your feedback. I have already finished the moving process and
the upgraded relay is already set up.
My server now runs FreeBSD 12.0 as a host, but with Tor in a FBSD 11.2 jail. I
will upgrade the jail to 12.0 when FreeBSD unbreaks Tor relays on OpenSSL 1.1.1.
I am starting wit