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If you find that your devices are already compatible with the regular mode, there isn't really a need to turn it on. Only turn it on if something doesn't connect. I suspect all Apple devices would connect fine either way.
 
With this Option you are disabling 5GHz Hotspot Mode and revert back to 2.4GHz. As my previous poster already said, turn it on if you have issues. Otherwise leave it as 5GHz is faster but has slower range.
 
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