Public bug reported:
Unison from Ubuntu 20.04 LTS (version unison=2.48.4-4ubuntu1) works well
with a client in exactly the same version, with exactly the same OS.
However, it does not work well with Unison 2.48.4-1ubuntu1 from Ubuntu
18.04, or with Unison on other OSes.
Once the client has deter
Note that I solved the incompatibility issue with Windows & Mac OS by
installing the former Debian version on the Ubuntu 20.04 LTS server:
```
wget
http://ftp.fr.debian.org/debian/pool/main/u/unison/unison_2.48.4-1+b1_amd64.deb
sudo dpkg -i unison_2.48.4-1+b1_amd64.deb
```
Running that breaked t
