It does appear to have been removed from all documentation for the most recent versions. Considering how different the various revisions are I wouldn't be surprised if the current chips used don't support the feature. I just received a version 10 and I'm extremely pleased with the performance and range. It's about as good as any 2.4ghz router on the market and appears they've boosted the power output on versions 10 and 11. Only version 11 appears to support IPv6,

What is the radius or the diameter (approx) of the range that you receive?

Do you live in a house or a condo? The walls are thick?

Soporte Argentina wrote

What is the radius or the diameter (approx) of the range that you receive?

Do you live in a house or a condo? The walls are thick?

I researched the chipset family used in the TL-WR841N/ND hardware versions 9,10,11 and they claim to support 2x2:2 MIMO, which makes sense considering it has two antennas. It may be that they no longer advertise the feature because it's considered to be standard nowadays and not a feature worth mentioning with the more recent models.

The range I receive is excellent considering these routers have their power amplifiers built right into the SoC processor. Most routers have additional power amplifier chips that are external from the processor and also use separate radio chips as well. With hardware version 9,10 and 11 of this model the CPU, radio/transmitter, amplifier and network switch are all built into a single processor. I believe this allows for a more stable/simple router and have been surprised at how little heat mine produces. The range is good enough to cover my 2200 sq/ft bungalow including basement and the outside perimeter of the house. I find my laptop with a high-end wireless adapter gets the best range, so the quality of the WiFi adapter in your devices definitely makes a difference. I've also found that when the signal is low due to being far from the router that it still manages to produce a fast and reliable connection.

So far my version 10 has been very stable and cool running with no issues whatsoever to report as of yet. The version 10 is basically a refined version 9 with the processor running 100mhz faster. If you are looking to purchase one I definitely recommend this model and suggest ensuring you get a version 10 as there are still a lot of version 9's out there. I got mine from Amazon since all the local stores I checked were still selling version 9. There is also a version 11 as well but it isn't widely available yet. I live in Canada and visited the TP Link head office and they hadn't even received any version 11's yet.

Hope this helps.