Many thanks for posting the first thread with an actually useful title.
I eventually found the change log (because I hate installing updates without knowing what the differences are):
https://minion.gg/?log
Underlying problem was that the certificate expired (which means it is no longer trusted by the system ... firewall/antivirus/network connections etc), so the update is a fresh certificate.
Installation instructions are here:
https://www.esoui.com/forums/showthread.php?t=8082
Which boils down to :
* Uninstall first, but keep configuration directory intact
* Install the 32-bit version from minion.gg (not the 64-bit version, I don't know why, it doesn't say)
* On first execution only, run with admin privs
* Check the firewall if you continue getting the 'cannot connect' error, just in case your firewall wants the new executable to be on the whitelist.
More detailed instructions in the link.