>I can't imagine altitude itself would have nearly as much of an impact on general equipment functionality than the related changes in temperature and humidity.
The problem is the air pressure.
Heat transfer (such as via heat sinks) is affected by air pressure. The lower the pressure the worse the cooling efficiency. Also fans get affected as the air thins.
If you take it to the extreme - this is a serious issue of satellites. It can be -200 degrees celcius, but because there is no air pressue (or air mass), there is no way to dissapate heat from inside of the satellite to the outside. How do you cool a nuclear reactor in space?
By the time you get to 10km of altitude, the cooling issue is already becoming an issue.
Lubrication (such as bearing lubrication in fans) can also be an issue. As you lower the air pressure, lubricants are more likely to leak out - less pressure to keep them squeezed in.
Antminer even provide some specification guidance for their products:
https://support.bitmain.com/hc/en-us/articles/900000261726-S19-Pro-Specifications
"When the miner is used at an altitude from 900m to 2000m, the highest operating temperature decreases by 1℃ for every increase of 300m"
I have never head of, nor think Meraki have any ambitions for making products to operate at "altitude". IMHO - I would try and stick to operating Meraki equipment below 2000m.
