I have to imagine I'm not the only one installing ArcGIS Server 11.5 and getting surprised when the installer starts indicating that it's configuring ArcGIS Server 11.3. The pop up that clarifies that the 11.3 patch is required for 11.5 pops up way later (and after I cancelled).
For those who haven't yet, just give it a bit to do its thing and everything is fine.
