First of all, how do I know which version of IIS I was running? When you are hosting multiple domains, the default IIS website home page is not likely going to be the IIS start page. So checking the default website home page usually does not work. I opened Windows Task Manager, and selected "Show processes from all users":
Then I right clicked on "w3wp.exe", and on its popup menu, I clicked on "Properties":
Then I clicked on the "Details" tab:
I see that the version number is 7.5…
Now about the SSL certificate installation.
First I installed my new multi-domain certificate by clicking on the "Server Certificates" icon in the IIS Manager Home pane.
The certificate is not applied to any of the websites at this point. I went to the "Bindings…" menu of each website, and edited the https port 443 bindings. I selected the new certificate for each website. I ran into a problem immediately. IIS started to shut down my sites, saying that the port 443 was in use. This is because the "Host name:" field for https binding is always read-only and always blank, even though I had a valid host header value for port 443 before. After the certificate selection, IIS actually changed the host headers to blanks! As a result, all my sites tried to respond to all requests on port 443.
At this point, I had to fix them from the command line. First, I navigated into the "C:\Windows\System32\inetsrv" directory, and then I ran the following command:
appcmd set site /site.name:"IIS Site Name
The "IIS Site Name
appcmd set site /site.name:"IIS Site Name" /+bindings.[protocol='https',bindingInformation='*:443:www.*******.com
That completed the renewal.