IIS Version 7.0 or greater is required to install [whatever extension is not working] is an error given when trying to install an IIS extension on IIS 10. According to Windows/IIS forums, it is a common problem in IIS 10 where the installer isn't able to get the IIS Version. Who knows why or how this is still an issue but lucky I have found a solution.

After hours of looking at how to install IIS SEO Toolkit 1.0, I found this. Multiple other solutions had me editing the registry in another location with no progress made trying to install the extension. So here is the solution I found.

If you get this error you can try to edit these registry keys:

Note: Option 1 did not accomplish anything in the process for me, but is still an option to try.

1. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W3SVC\Parameters
   • Select MajorVersion
   • Change the Base from Hexadecimal to Decimal
   • Edit the Value date to 9
   • Click OK and then either hit F5 or go to View > Refresh
2. HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\InetStp
   • Select MajorVersion
   • Change the Base from Hexadecimal to Decimal
   • Edit the Value date to 9
   • Click OK and then either hit F5 or go to View > Refresh

After you complete this process you can then install the IIS Extension. After completing said installation, you can return to these registry keys and follow the same process changing the value back to decimal value 10.

Special thanks to Idrees' Blog for writing this article in 2018.

Additionally, for anyone looking, you can download the last official supported version of IIS SEO Toolkit here which was downloaded from Internet Archive here.