FYI, I see RU Server 188.8.131.52 beta version posted, but wasn't included in the release notes page.
There was in fact one change that is also mentioned in releases notes for Remote Utilities. Here it is: Added: Viewer-to-RUServer and Host-to-RUServer authorization is now TLS 1.2 based instead of RSA, which makes authorization on the server significantly faster
Also, when updating RU Server, it looks like it cannot properly close and update RU files and pops up a message that a reboot maybe (is?) necessary. Having a smoother upgrade process that doesn't require a reboot would be preferred for self hosted servers.
This is standard for many running services. You may notice the same when updating the Host, for example. Just click OK in prompt windows. Reboot may not be necessary.