Yes, it's also for the versions after XP.
Another thing to be careful of is that a MIDI device's "ID" within the OS is linked to the USB port it's plugged into, so if you plug the same device into 2 or 3 different USB ports from time to time, it will be seen as 2 or 3 different MIDI devices by the OS.
Also, even if you disconnect a MIDI device, it will still be registered within the OS!
This means it can be easy to exceed the limit without realizing it. I forget whether it's Roland or Korg, but one of them has a USB MIDI driver utility that will list all of the MIDI devices which are registered within the OS, and will let you remove any that are no longer being used.
PS-- That's how I learned that the Microsoft GS Wavetable Synth counts as a MIDI device-- I was using the utility to remove extra "devices" from where I'd shuffled my keyboards back and forth between different USB ports, and noticed that the Wavetable Synth was listed as one of the MIDI output devices.
By the way, I think it's 10 MIDI input devices and 10 MIDI output devices-- in other words, I think it might be possible to have more than 10 MIDI devices connected as long as some of them have MIDI In ports only, and others have MIDI Out ports only. But I'm not certain of that!