Welcome to Android Central! It doesn't have to do with the OS version. As long as the device has a wi-fi radio that connects to 2.4 GHz (and pretty much every phone should be able to), it should connect. Which device do you have? Have you checked the wi-fi settings to make sure it's set to look for 2.4 GHz, or both 2.4 and 5 GHz? There might be a setting that selects only 5 GHz.