While it is still free…
The current version: http://reflector.red-gate.com/Reflector.zip
The “Check for Updates” entry in the “Help” menu checks this URL: http://reflector.red-gate.com/Reflector.version
Which currently returns:
6.6.0.30
6.1.0.0
http://reflector.red-gate.com/Download.aspx?File=Reflector&Client={Client}&Version={Version}
When Reflector detects there is a new version, you get a dialog like this:
—————————
.NET Reflector
—————————
A new version of .NET Reflector is available. Do you want to install automatically?
—————————
Yes No
—————————
When you press [Yes], it starts downloading from a URL that depends on the current version: http://reflector.red-gate.com/Download.aspx?File=Reflector&Client=Reflector&Version=6.5.0.135
{Client} was replaced by Reflector, and {Version} was replaced by 6.5.0.135 (the version of the currently running Reflector).
–jeroen