unRAID 5 is a moving target. Maybe unMenu changed, you may have to install unRAID manually. The two files are the install buttons I'm assuming. I've got to get a shipment out but I'll take a look later if I get a chance.
I came to post that I'm having the same issue but I'm on 4.7. My unmenu didn't seem to be the newest version so I just now updated it and restarted it and I'm still seeing the same issue. I click the check for update button, the page refreshes, but nothing ever changes. There is nothing at the bottom of the page as expected. I have no problem installing it manually but I'm free for testing if you need.
Nothing is output to the syslog when I click the check for update button but if you want one anyways then let me know.
I too have the same issue with 4.7
Same problem here... running 5.0beta9