Ewww
The reason I'd imagine that you cannot get to the https file is that the package upgrade has not generated the certificates.
A quick workaround should be to go into /etc/cups/client.conf and comment out the lines
Encryption Always Encryption Required and Encryption Never
Then restart cups This should put it back to what was/is the default of Encryption if the client requests it.
After you have restarted cups you should be able to access the http web interface again and your printers should start working again without authentication